{"id":22650,"date":"2025-10-22T01:22:57","date_gmt":"2025-10-21T23:22:57","guid":{"rendered":"https:\/\/www.jgclassics.com\/2025\/10\/22\/crankcase-ventilation-systems-on-ventoux-engines\/"},"modified":"2025-10-22T10:30:48","modified_gmt":"2025-10-22T08:30:48","slug":"crankcase-ventilation-systems-on-ventoux-engines","status":"publish","type":"post","link":"https:\/\/www.jgclassics.com\/en\/2025\/10\/22\/crankcase-ventilation-systems-on-ventoux-engines\/","title":{"rendered":"Crankcase ventilation systems on Ventoux engines"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"22650\" class=\"elementor elementor-22650 elementor-22596\" data-elementor-post-type=\"post\">\n\t\t\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-5753eadc elementor-section-boxed elementor-section-height-default elementor-section-height-default\" 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(English)\">\n\t\t\t\t\t                                    <img decoding=\"async\"\n            class=\"wpml-ls-flag\"\n            src=\"https:\/\/www.jgclassics.com\/wp-content\/plugins\/sitepress-multilingual-cms\/res\/flags\/en.svg\"\n            alt=\"\"\n            loading=\"lazy\"\n            width=18\n            height=12\n    \/><span class=\"wpml-ls-native\">English<\/span><\/a>\n\t\t\t<\/li><li class=\"wpml-ls-slot-shortcode_actions wpml-ls-item wpml-ls-item-fr wpml-ls-last-item wpml-ls-item-legacy-list-horizontal\">\n\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/fr\/\" hreflang=\"fr\" lang=\"fr\" class=\"wpml-ls-link\" aria-label=\"Switch to French (Fran\u00e7ais)\" title=\"Switch to French (Fran\u00e7ais)\">\n\t\t\t\t\t                                    <img decoding=\"async\"\n            class=\"wpml-ls-flag\"\n            src=\"https:\/\/www.jgclassics.com\/wp-content\/plugins\/sitepress-multilingual-cms\/res\/flags\/fr.svg\"\n            alt=\"\"\n            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elementor-element elementor-element-138c4407 elementor-section-full_width elementor-section-height-min-height elementor-section-stretched elementor-section-height-default elementor-section-items-middle\" data-id=\"138c4407\" data-element_type=\"section\" data-e-type=\"section\" data-settings=\"{&quot;stretch_section&quot;:&quot;section-stretched&quot;}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-no\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-3bd6d333\" data-id=\"3bd6d333\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-7ad34c86 elementor-invisible elementor-widget elementor-widget-image\" data-id=\"7ad34c86\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"1019\" height=\"770\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-01_detail_final.jpg\" class=\"attachment-1536x1536 size-1536x1536 wp-image-22639\" alt=\"Renault Ventoux 670-01 engine\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-01_detail_final.jpg 1019w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-01_detail_final-300x227.jpg 300w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-01_detail_final-768x580.jpg 768w\" sizes=\"(max-width: 1019px) 100vw, 1019px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-6882606a elementor-widget__width-inherit elementor-invisible elementor-widget elementor-widget-heading\" data-id=\"6882606a\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInDown&quot;}\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h1 class=\"elementor-heading-title elementor-size-default\">Crankcase ventilation systems on Ventoux engines<\/h1>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-42e091c elementor-widget__width-inherit elementor-invisible elementor-widget elementor-widget-heading\" data-id=\"42e091c\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInDown&quot;}\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Breathe or bust: how Renault solved crankcase ventilation on Ventoux engines of the 1950s and 1960s<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-4f6bcab6 elementor-widget elementor-widget-post-info\" data-id=\"4f6bcab6\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"post-info.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<ul class=\"elementor-inline-items elementor-icon-list-items elementor-post-info\">\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item elementor-repeater-item-6869cb2 elementor-inline-item\" itemprop=\"author\">\n\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/en\/author\/jgclassics_hikp0z\/\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t\t<i aria-hidden=\"true\" class=\"far fa-user-circle\"><\/i>\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text elementor-post-info__item elementor-post-info__item--type-author\">\n\t\t\t\t\t\t\t\t\t\tJG Classics Administrator\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t<\/li>\n\t\t\t\t<li class=\"elementor-icon-list-item elementor-repeater-item-a911f47 elementor-inline-item\" itemprop=\"datePublished\">\n\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/en\/2025\/10\/22\/\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t\t<i aria-hidden=\"true\" class=\"fas fa-calendar\"><\/i>\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text elementor-post-info__item elementor-post-info__item--type-date\">\n\t\t\t\t\t\t\t\t\t\t<time>October 22, 2025<\/time>\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t<\/li>\n\t\t\t\t<li class=\"elementor-icon-list-item elementor-repeater-item-5aa2e53 elementor-inline-item\">\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t\t<i aria-hidden=\"true\" class=\"far fa-clock\"><\/i>\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text elementor-post-info__item elementor-post-info__item--type-time\">\n\t\t\t\t\t\t\t\t\t\t<time>1:22 am<\/time>\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t<\/ul>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-11d7b4e elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"11d7b4e\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-742acb2\" data-id=\"742acb2\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-c3ec336 elementor-widget elementor-widget-heading\" data-id=\"c3ec336\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">The general principle<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-6024b31 elementor-widget elementor-widget-text-editor\" data-id=\"6024b31\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>In a combustion engine, a small part of the gases in the combustion chamber pass between the piston rings into the crankcase: this is known as <em>blow-by<\/em>.<br>This mixture of gases and oil vapor increases the internal pressure and, if not properly evacuated, ends up pushing the oil through any weak point: seals, oil seals or even the dipstick.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-438693c elementor-widget elementor-widget-text-editor\" data-id=\"438693c\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>The mission of the crankcase ventilation system is as simple as it is vital: to <strong>keep the internal pressure balanced<\/strong> and allow these gases to escape without entraining oil.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-9eac785 elementor-widget elementor-widget-text-editor\" data-id=\"9eac785\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>In modern engines, a <a href=\"https:\/\/es.wikipedia.org\/wiki\/Sistema_de_ventilaci%C3%B3n_de_gases_del_c%C3%A1rter_(PCV)\" target=\"_blank\" rel=\"noopener\">PCV valve<\/a> connects the crankcase to the intake, using the manifold vacuum to draw in gases.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-d3c5e37 elementor-widget elementor-widget-text-editor\" data-id=\"d3c5e37\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>The main function of the <strong>crankcase breather<\/strong> is to relieve the pressure built up by the blow-by gases leaking from the cylinders, preventing this pressure from forcing the oil out through seals and gaskets. If the ventilation is deficient or obstructed, the engine will try to expel the pressure &#8220;wherever it can&#8221;, causing oil leaks at oil seals, gaskets and even causing the dipstick to partially pop out. This system is often overlooked, but in veteran engines inadequate ventilation can be the &#8220;silent culprit&#8221; of abnormal oil consumption and persistent leaks.  <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-0759a5c elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"0759a5c\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-7fc11af\" data-id=\"7fc11af\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-6589a44 elementor-widget elementor-widget-heading\" data-id=\"6589a44\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Crankcase breathing in Ventoux engines<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-d180327 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"d180327\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-6b3535e\" data-id=\"6b3535e\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-b8fe71f elementor-widget elementor-widget-image\" data-id=\"b8fe71f\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/motor-670-05.jpg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"engine 670-05\" data-elementor-lightbox-description=\"Renault Dauphine Gordini 670-05 Engine\" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MjI2NDAsInVybCI6Imh0dHBzOlwvXC93d3cuamdjbGFzc2ljcy5jb21cL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjVcLzEwXC9tb3Rvci02NzAtMDUuanBnIn0%3D\">\n\t\t\t\t\t\t\t<img decoding=\"async\" width=\"937\" height=\"788\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/motor-670-05.jpg\" class=\"attachment-large size-large wp-image-22640\" alt=\"Renault Dauphine Gordini 670-05 Engine\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/motor-670-05.jpg 937w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/motor-670-05-300x252.jpg 300w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/motor-670-05-768x646.jpg 768w\" sizes=\"(max-width: 937px) 100vw, 937px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-93a3591\" data-id=\"93a3591\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-6a96fb4 elementor-widget__width-initial elementor-widget elementor-widget-text-editor\" data-id=\"6a96fb4\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>Renault Ventoux engines (4CV, Dauphine, Gordini, Ondine and early Floride) <strong>had no intake depression<\/strong>: they relied on passive vents and the balance of natural pressures inside the block and employed an open system that let gases and oil vapors escape directly to the atmosphere.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-2c3a087 elementor-widget__width-initial elementor-widget elementor-widget-text-editor\" data-id=\"2c3a087\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>Throughout the life of the Ventoux engine, Renault adopted different solutions: from simple breather caps with grille, to vent pipes located in the rocker cover or in the block. Below, we will see the historical evolution of these solutions according to the versions of the engine (identified by references such as <em>Type 662<\/em> on the 4CV, <em>670-01\/02<\/em> on standard Dauphine, <em>670-04<\/em> and <em>670-05<\/em> on Dauphine Gordini. <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-78e898e elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"78e898e\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-c66ce86\" data-id=\"c66ce86\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-568d5dd elementor-widget elementor-widget-heading\" data-id=\"568d5dd\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">First versions: Renault 4CV (Type 662 engine)<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-9e776c4 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"9e776c4\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-ebb569d\" data-id=\"ebb569d\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-72b889c elementor-widget elementor-widget-text-editor\" data-id=\"72b889c\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>The small Renault 4CV, produced since 1947, inaugurated the Billancourt\/Ventoux engine family with displacements of 760 cc (initial version Type 662-1) and then 747 cc (Type 662-2). In its early years, the crankcase ventilation of the 4CV was entrusted to : <\/p>\n<ul>\n<li><strong>A breather<\/strong> was the <strong>oil filler cap<\/strong> itself, designed with an internal filter element to let the vapors escape. This configuration was typical for engines of the time, with no air cleaner connections or check valves. <\/li>\n<\/ul>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-3bb00d9 elementor-widget elementor-widget-image\" data-id=\"3bb00d9\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/renault4CV_motor_respiradero-scaled.jpg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"Ventoux Renault 4CV engine\" data-elementor-lightbox-description=\"Renault 4CV Ventoux engine. See crankcase breather on engine block. \" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MjI2NDEsInVybCI6Imh0dHBzOlwvXC93d3cuamdjbGFzc2ljcy5jb21cL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjVcLzEwXC9yZW5hdWx0NENWX21vdG9yX3Jlc3BpcmFkZXJvLXNjYWxlZC5qcGcifQ%3D%3D\">\n\t\t\t\t\t\t\t<img decoding=\"async\" width=\"1024\" height=\"709\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/renault4CV_motor_respiradero-1024x709.jpg\" class=\"attachment-large size-large wp-image-22641\" alt=\"Renault 4CV Ventoux engine. Crankcase breather\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/renault4CV_motor_respiradero-1024x709.jpg 1024w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/renault4CV_motor_respiradero-300x208.jpg 300w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/renault4CV_motor_respiradero-768x531.jpg 768w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/renault4CV_motor_respiradero-1536x1063.jpg 1536w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/renault4CV_motor_respiradero-2048x1417.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-3555430\" data-id=\"3555430\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-a0e0aaf elementor-widget elementor-widget-image\" data-id=\"a0e0aaf\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ventilo-tapa-valvulas.jpg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"Renault 4CV rocker arm cover\" data-elementor-lightbox-description=\"Renault 4CV rocker cover (model 1062). All of them use the vented plug. Although some of them have a venting pipette.  \" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MjI2NDIsInVybCI6Imh0dHBzOlwvXC93d3cuamdjbGFzc2ljcy5jb21cL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjVcLzEwXC92ZW50aWxvLXRhcGEtdmFsdnVsYXMuanBnIn0%3D\">\n\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"826\" height=\"770\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ventilo-tapa-valvulas.jpg\" class=\"attachment-large size-large wp-image-22642\" alt=\"Renault 4CV rocker arm cover\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ventilo-tapa-valvulas.jpg 826w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ventilo-tapa-valvulas-300x280.jpg 300w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ventilo-tapa-valvulas-768x716.jpg 768w\" sizes=\"(max-width: 826px) 100vw, 826px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-d45b927 elementor-widget elementor-widget-text-editor\" data-id=\"d45b927\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<ul><li><strong>A vent on the right side of the <\/strong>engine <strong>block <\/strong>that evacuated the excess pressure to the atmosphere. A vent whose tube length (exactly 67 mm) was carefully measured to generate the outflow of gases, surely helping their evacuation by Venturi effect during the running of the vehicle, and avoiding that this vent became a source of &#8220;back pressure&#8221; towards the crankcase (causing the opposite effect to the desired one). You can see <a href=\"https:\/\/www.jgclassics.com\/en\/2025\/10\/22\/crankcase-ventilation-systems-on-ventoux-engines\/#RESPIRADERO_4CV\" data-wplink-edit=\"true\">here an illustration<\/a> of the manual of the time<\/li><\/ul>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-78209c8 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"78209c8\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-0144428\" data-id=\"0144428\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-6b88518 elementor-widget__width-initial elementor-widget elementor-widget-text-editor\" data-id=\"6b88518\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>On some later versions of the Renault 4CV it is possible to find an <strong>additional breather pipe<\/strong> located at the top of the engine. This pipe came out of the rocker cover and allowed a more efficient <strong>&#8220;venting&#8221; of<\/strong> the crankcase gases. <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-2d5f8f1 elementor-widget__width-initial elementor-widget elementor-widget-text-editor\" data-id=\"2d5f8f1\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>In other words, the 4CV (depending on the versions) came to have <strong>three <\/strong>breathing <strong>points <\/strong>available in which it was possible to install closed plug having then either <strong>two breathing points <\/strong>(pipette in the engine block+outlet pipe of the rocker cover<strong>)- or three ventilation points <\/strong>(pipette in the engine block+outlet pipe of the rocker cover+ventilated plug).<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-f4fe58a\" data-id=\"f4fe58a\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-47e8571 elementor-widget__width-initial elementor-widget elementor-widget-image\" data-id=\"47e8571\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/renault-4CV-motor.jpg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"renault 4CV engine\" data-elementor-lightbox-description=\"Renault 4CV engine. Note the breather on the right rear side of the rocker cover. \" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MjI2NDMsInVybCI6Imh0dHBzOlwvXC93d3cuamdjbGFzc2ljcy5jb21cL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjVcLzEwXC9yZW5hdWx0LTRDVi1tb3Rvci5qcGcifQ%3D%3D\">\n\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"937\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/renault-4CV-motor-1024x937.jpg\" class=\"attachment-large size-large wp-image-22643\" alt=\"Renault 4CV engine. Note the breather on the right rear side of the rocker cover.\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/renault-4CV-motor-1024x937.jpg 1024w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/renault-4CV-motor-300x275.jpg 300w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/renault-4CV-motor-768x703.jpg 768w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/renault-4CV-motor.jpg 1440w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Renault 4CV engine. Note the breather on the right rear side of the rocker cover. <\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-0369f7e elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"0369f7e\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-a0b28b0\" data-id=\"a0b28b0\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-726b28b elementor-widget elementor-widget-text-editor\" data-id=\"726b28b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>Be that as it may, the criticality of these points is empirically proven and there have been 4CV owners who have reported that a cleaning of these vents has immediate effects: <em>&#8220;I cleaned the bouchon reniflard and it seems that the engine no longer leaks oil&#8221;<\/em> said an owner of a 1959 4CV which illustrates how the clogging of the vented plug could cause leaks that were solved by restoring the ventilation (actually we <a href=\"https:\/\/www.jgclassics.com\/en\/2025\/10\/18\/my-classic-car-is-leaking-oil-v-engine-breather-and-crankcase-ventilation-problems\/\" target=\"_blank\" rel=\"noopener\">can also attest<\/a> to this :-)). <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-ea25c50 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"ea25c50\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-dc5512a\" data-id=\"dc5512a\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-d9a7dac elementor-widget elementor-widget-menu-anchor\" data-id=\"d9a7dac\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"menu-anchor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-menu-anchor\" id=\"RESPIRADERO_4CV\"><\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-9f8a87e elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"9f8a87e\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-33 elementor-top-column elementor-element elementor-element-5c8bf82\" data-id=\"5c8bf82\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-da5e87b elementor-widget elementor-widget-image\" data-id=\"da5e87b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/respiradero-bloque-motor-renault-4CV.jpg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"engine block breather renault 4CV\" data-elementor-lightbox-description=\"engine block breather renault 4CV\" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MjI2NDQsInVybCI6Imh0dHBzOlwvXC93d3cuamdjbGFzc2ljcy5jb21cL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjVcLzEwXC9yZXNwaXJhZGVyby1ibG9xdWUtbW90b3ItcmVuYXVsdC00Q1YuanBnIn0%3D\">\n\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"380\" height=\"297\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/respiradero-bloque-motor-renault-4CV.jpg\" class=\"attachment-large size-large wp-image-22644\" alt=\"engine block breather renault 4CV\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/respiradero-bloque-motor-renault-4CV.jpg 380w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/respiradero-bloque-motor-renault-4CV-300x234.jpg 300w\" sizes=\"(max-width: 380px) 100vw, 380px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">engine block breather renault 4CV<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-33 elementor-top-column elementor-element elementor-element-a9e8345\" data-id=\"a9e8345\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-d4dc98f elementor-widget elementor-widget-image\" data-id=\"d4dc98f\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/respiradero-bloque-motor-renault-4CV-cotas.jpg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"engine block breather renault 4CV-cotas\" data-elementor-lightbox-description=\"renault 4CV engine block breather. Detail of assembly dimensions \" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MjI2NDUsInVybCI6Imh0dHBzOlwvXC93d3cuamdjbGFzc2ljcy5jb21cL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjVcLzEwXC9yZXNwaXJhZGVyby1ibG9xdWUtbW90b3ItcmVuYXVsdC00Q1YtY290YXMuanBnIn0%3D\">\n\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"272\" height=\"363\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/respiradero-bloque-motor-renault-4CV-cotas.jpg\" class=\"attachment-large size-large wp-image-22645\" alt=\"renault 4CV engine block breather. Detail of assembly dimensions\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/respiradero-bloque-motor-renault-4CV-cotas.jpg 272w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/respiradero-bloque-motor-renault-4CV-cotas-225x300.jpg 225w\" sizes=\"(max-width: 272px) 100vw, 272px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-33 elementor-top-column elementor-element elementor-element-6224e68\" data-id=\"6224e68\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-935631d elementor-widget elementor-widget-text-editor\" data-id=\"935631d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><strong data-start=\"209\" data-end=\"227\">First image (photo)<\/strong>, the classic Renault 4CV engine block side <em data-start=\"240\" data-end=\"251\">reniflard<\/em>: a calibrated tube that evacuates crankcase vapors to the outside.<br data-start=\"364\" data-end=\"367\"><strong data-start=\"367\" data-end=\"383\">Second image (drawing)<\/strong>, the original diagram from the workshop manual indicating the exact length (67 mm) that the tube must protrude, essential to avoid both air suction by Venturi effect and the projection of oil to the outside.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-665964c elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"665964c\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-c216c64\" data-id=\"c216c64\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-d3faab5 elementor-widget elementor-widget-heading\" data-id=\"d3faab5\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Renault Dauphine standard (engine Type 670)<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-3db49d4 elementor-widget elementor-widget-text-editor\" data-id=\"3db49d4\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>The Renault Dauphine (project R1090), launched in 1956, equipped an enlarged version of the Ventoux engine &#8211; 845 cc &#8211; known as <em>Type 670-01<\/em> (27-31 hp according to standard). From its inception, the Dauphine incorporated a venting system very similar to the later 4CV scheme, i.e. with <strong>a fixed breather mounted <\/strong>on the block <strong>plus a vented filler cap.<\/strong> The block-mounted breather system disappeared on the 670-02 engine and no longer appeared on the Dauphine (or Gordini), leaving either the vented plug, the side pipe (670-05) or a combination of the two.  <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-ed3208f elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"ed3208f\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-e083ce7\" data-id=\"e083ce7\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-1cc5d9a elementor-widget elementor-widget-image\" data-id=\"1cc5d9a\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-01_detail_final.jpg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"Renault Ventoux 670-02 engine\" data-elementor-lightbox-description=\"Renault Ventoux 670-01 engine. The 670-01 still has the crankcase ventilation pipette on the engine block. \" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MjI2MzksInVybCI6Imh0dHBzOlwvXC93d3cuamdjbGFzc2ljcy5jb21cL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjVcLzEwXC82NzAtMDFfZGV0YWlsX2ZpbmFsLmpwZyJ9\">\n\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1019\" height=\"770\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-01_detail_final.jpg\" class=\"attachment-large size-large wp-image-22639\" alt=\"Renault Ventoux 670-01 engine\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-01_detail_final.jpg 1019w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-01_detail_final-300x227.jpg 300w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-01_detail_final-768x580.jpg 768w\" sizes=\"(max-width: 1019px) 100vw, 1019px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Renault Ventoux 670-01 engine. The 670-01 still has the crankcase ventilation pipette on the engine block. <\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-9d8317a\" data-id=\"9d8317a\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-2cef7da elementor-widget elementor-widget-image\" data-id=\"2cef7da\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-02_detail_final.jpg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"Renault Ventoux 670-02 engine\" data-elementor-lightbox-description=\"Renault Ventoux 670-02 engine. Note the absence of crankcase ventilation pipette on the engine block. \" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MjI2NDYsInVybCI6Imh0dHBzOlwvXC93d3cuamdjbGFzc2ljcy5jb21cL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjVcLzEwXC82NzAtMDJfZGV0YWlsX2ZpbmFsLmpwZyJ9\">\n\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"840\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-02_detail_final-1024x840.jpg\" class=\"attachment-large size-large wp-image-22646\" alt=\"Renault Ventoux 670-02 engine\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-02_detail_final-1024x840.jpg 1024w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-02_detail_final-300x246.jpg 300w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-02_detail_final-768x630.jpg 768w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/670-02_detail_final.jpg 1405w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Renault Ventoux 670-02 engine. Note the absence of crankcase ventilation pipette on the engine block. <\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-42e43c0 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"42e43c0\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-92ec8fb\" data-id=\"92ec8fb\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-40fe452 elementor-widget elementor-widget-text-editor\" data-id=\"40fe452\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>On the <strong data-start=\"162\" data-end=\"180\">Renault 670-04<\/strong> engine, crankcase ventilation was provided by a <strong data-start=\"285\" data-end=\"331\">filler cap with integrated breather<\/strong>, visible on the top of the rocker cover. This plug, equipped with a small <strong data-start=\"425\" data-end=\"455\">metal filtering screen<\/strong>, allowed the crankcase gases to pass to the outside, keeping the internal pressure balanced.<br data-start=\"560\" data-end=\"563\">The cover also incorporated a <strong data-start=\"593\" data-end=\"623\">small inner baffle<\/strong> that acted as an oil separator, preventing the droplets in suspension from escaping together with the vapors. This system, although simple, proved effective for the speeds and operating conditions of the standard Dauphine and was the basis on which Renault evolved the later 670-05 type Ventoux engines of the Gordini versions.  <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-c914312\" data-id=\"c914312\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-13f8179 elementor-widget elementor-widget-image\" data-id=\"13f8179\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/dauphine_670-04_despiece.1.jpg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"Renault Dauphine engine: Rocker arm covers engine 670-04\" data-elementor-lightbox-description=\"Renault Dauphine engine: 670-04 engine rocker cover. Use of ventilated cap with breather. \" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MjI2NDcsInVybCI6Imh0dHBzOlwvXC93d3cuamdjbGFzc2ljcy5jb21cL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjVcLzEwXC9kYXVwaGluZV82NzAtMDRfZGVzcGllY2UuMS5qcGcifQ%3D%3D\">\n\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"673\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/dauphine_670-04_despiece.1-1024x673.jpg\" class=\"attachment-large size-large wp-image-22647\" alt=\"Renault Dauphine engine: Rocker arm covers engine 670-04\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/dauphine_670-04_despiece.1-1024x673.jpg 1024w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/dauphine_670-04_despiece.1-300x197.jpg 300w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/dauphine_670-04_despiece.1-768x505.jpg 768w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/dauphine_670-04_despiece.1-1536x1009.jpg 1536w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/dauphine_670-04_despiece.1-2048x1346.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Renault Dauphine engine: 670-04 engine rocker cover. Use of ventilated cap with breather. <\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-b181e11 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"b181e11\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-a53da45\" data-id=\"a53da45\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-fe9d590 elementor-widget elementor-widget-text-editor\" data-id=\"fe9d590\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>Be that as it may, the function of both the vented plug and the rocker cover gas outlet was to retain the oil particles (which drained back into the engine) and let only the gases pass through.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-ed7e748 elementor-widget elementor-widget-text-editor\" data-id=\"ed7e748\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>The Dauphine, like the R4CV, did not recirculate these gases to the intake either; it simply expelled them. As a technical publication points out, <strong>the Ventoux engines relied on these direct atmospheric exhausts for all their ventilation<\/strong>. <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-f157ad6 elementor-widget elementor-widget-text-editor\" data-id=\"f157ad6\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>In practice, a Dauphine in good condition hardly smoked at all from the breather; but on worn units it was notorious to see the <em>&#8220;second exhaust&#8221;<\/em> blowing bluish-white smoke from the rocker cover tube. This was a symptom of excessive <g id=\"gid_1\">blow-by<\/g> (worn piston rings) and not a failure of the breather itself. However, <strong>if the breather was plugged<\/strong>, even if the engine was healthy, the internal pressure would rise rapidly when running on the road, with disastrous results: oil forced through seals, oil dipstick ejected and possibility of crankcase drained within a few kilometers.  <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-e50803e elementor-widget elementor-widget-heading\" data-id=\"e50803e\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Gordini sport versions: engines 670-05<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-670dafb elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"670dafb\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-def2fff\" data-id=\"def2fff\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-f644b69 elementor-widget elementor-widget-text-editor\" data-id=\"f644b69\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>Renault offered from 1957-58 a powered version of the Dauphine developed by Am\u00e9d\u00e9e Gordini. At the end of 1960, an evolution identified as <em>Type 670-05<\/em> appeared, power 40 hp SAE, ~36 hp DI but with internal design changes. As for the <strong>crankcase ventilation system<\/strong>, were there any differences?  <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-2aeaf61 elementor-widget elementor-widget-text-editor\" data-id=\"2aeaf61\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>The answer is <strong>yes<\/strong>, mainly related to improvements in the oil retention system on the rear crankshaft (i.e. gearbox side).<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-c2fb2f0 elementor-widget elementor-widget-text-editor\" data-id=\"c2fb2f0\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>On the 670-05 engine (used since 1960 on Gordini R1091\/1092, and also on the base R8 years later) a modification was introduced at the rear of the crankshaft: <strong>a helical &#8220;pigtail&#8221; spline<\/strong> around the rear journal, the effect of which was to return the oil to the engine by centrifugal action.  <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-c3f1aa6\" data-id=\"c3f1aa6\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-5aa3e7d elementor-widget elementor-widget-image\" data-id=\"5aa3e7d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/dauphine_670-05_despiece.1-scaled.jpg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"Renault Dauphine engine: Rocker cover engine 670-05\" data-elementor-lightbox-description=\"Renault Dauphine engine: Engine rocker cover 670-05. Use of closed cap entrusting the ventilation to the side breather. \" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MjI2NDgsInVybCI6Imh0dHBzOlwvXC93d3cuamdjbGFzc2ljcy5jb21cL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjVcLzEwXC9kYXVwaGluZV82NzAtMDVfZGVzcGllY2UuMS1zY2FsZWQuanBnIn0%3D\">\n\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"659\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/dauphine_670-05_despiece.1-1024x659.jpg\" class=\"attachment-large size-large wp-image-22648\" alt=\"Renault Dauphine engine: Rocker cover engine 670-05\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/dauphine_670-05_despiece.1-1024x659.jpg 1024w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/dauphine_670-05_despiece.1-300x193.jpg 300w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/dauphine_670-05_despiece.1-768x494.jpg 768w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/dauphine_670-05_despiece.1-1536x988.jpg 1536w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/dauphine_670-05_despiece.1-2048x1317.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Renault Dauphine engine: Engine rocker cover 670-05. Use of closed cap entrusting the ventilation to the side breather. <\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-fc0bc15 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"fc0bc15\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-6bd949c\" data-id=\"6bd949c\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-94cbb53 elementor-widget elementor-widget-text-editor\" data-id=\"94cbb53\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>This design (similar to that used in VW and other engines of the time) improved the sealing at the rear outlet <strong>, reducing oil leakage<\/strong>, although it still did not include a rubber oil seal. Renault, relying on this improvement, <strong>eliminated the vented oil plug on the 670-05<\/strong>, equipping them with a normal sealed plug. In other words, on the 670-05 Gordini the only active breathing passage was the upper crankcase tube (cache-culbuteurs).  <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-ae0c228 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"ae0c228\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-f52900b\" data-id=\"f52900b\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-a2159df elementor-widget elementor-widget-image\" data-id=\"a2159df\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ciguenal-cola-de-cerdo-scaled.jpg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"pigtail crankshaft\" data-elementor-lightbox-description=\"Renault Dauphine engine - Pigtail crankshaft for oil control (new version)\" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MjI1MjMsInVybCI6Imh0dHBzOlwvXC93d3cuamdjbGFzc2ljcy5jb21cL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjVcLzEwXC9jaWd1ZW5hbC1jb2xhLWRlLWNlcmRvLXNjYWxlZC5qcGcifQ%3D%3D\">\n\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"652\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ciguenal-cola-de-cerdo-1024x652.jpg\" class=\"attachment-large size-large wp-image-22523\" alt=\"Renault Dauphine engine - Pigtail crankshaft for oil control (new version)\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ciguenal-cola-de-cerdo-1024x652.jpg 1024w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ciguenal-cola-de-cerdo-300x191.jpg 300w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ciguenal-cola-de-cerdo-768x489.jpg 768w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ciguenal-cola-de-cerdo-1536x978.jpg 1536w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ciguenal-cola-de-cerdo-2048x1305.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Renault Dauphine engine - Pigtail crankshaft for oil control (new version)<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-5e6ae61\" data-id=\"5e6ae61\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-22a3a9b elementor-widget elementor-widget-image\" data-id=\"22a3a9b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ciguenal-estrias.jpg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"crankshaft splines\" data-elementor-lightbox-description=\"Renault Dauphine engine - &quot;Straight spline&quot; crankshaft for oil control (old version)\" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MjI1MjQsInVybCI6Imh0dHBzOlwvXC93d3cuamdjbGFzc2ljcy5jb21cL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjVcLzEwXC9jaWd1ZW5hbC1lc3RyaWFzLmpwZyJ9\">\n\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"725\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ciguenal-estrias-1024x725.jpg\" class=\"attachment-large size-large wp-image-22524\" alt=\"Renault Dauphine engine - &quot;Straight spline&quot; crankshaft for oil control (old version)\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ciguenal-estrias-1024x725.jpg 1024w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ciguenal-estrias-300x212.jpg 300w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ciguenal-estrias-768x544.jpg 768w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ciguenal-estrias-1536x1087.jpg 1536w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ciguenal-estrias-2048x1449.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Renault Dauphine engine - \"Straight spline\" crankshaft for oil control (old version)<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-d7831a1 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"d7831a1\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-7678baf\" data-id=\"7678baf\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-8bcb2ff elementor-widget elementor-widget-text-editor\" data-id=\"8bcb2ff\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>In theory, the &#8220;pigtail&#8221; propeller should have been sufficient to control the oil and the original ventilation was sufficient.  <strong>What could happen in practice?<\/strong><\/p>\n<ul>\n<li>For the breather, the oil\/gas filtration area is on the inside of the rocker cover so a dirt blockage is not obvious to see. And if that outlet is clogged, the fact that it is the only one means that the crankcase gas evacuation functionality is seriously compromised. <\/li>\n<li>If for some reason an older crankshaft is fitted to a 670-05 engine &#8211; only with straight splines which, although less effective than the &#8220;queue de couchon&#8221; or &#8220;pigtail&#8221; spiral for retaining oil is technically possible &#8211; the original venting may be insufficient.<\/li>\n<\/ul>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-97d4183 elementor-widget elementor-widget-text-editor\" data-id=\"97d4183\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>Just this happened in the restoration of <a href=\"https:\/\/www.jgclassics.com\/en\/2025\/10\/18\/my-classic-car-is-leaking-oil-v-engine-breather-and-crankcase-ventilation-problems\/\" target=\"_blank\" rel=\"noopener\">our Gordini a few weeks ago<\/a>: a new crankshaft from old stock (fine spline type, corresponding to 670-04 engine) was installed in a 670-05 block. The result was that, even with a clean cover breather, the engine was still leaking some oil out of the clutch bell under demanding use.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-56449c9 elementor-widget elementor-widget-text-editor\" data-id=\"56449c9\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>It is important to mention that oil retention systems without rubber seals based on spline or coil machining work well, but they are based on one premise: <strong>The pressures on both sides of the oil sump wall must be balanced.<\/strong> An overpressure will cause the grooves or spirals to become precisely the outlet path.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-b1c9638 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"b1c9638\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-560bb7d\" data-id=\"560bb7d\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-8179d67 elementor-widget elementor-widget-text-editor\" data-id=\"8179d67\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>And one solution is to add the ventilation that these &#8220;old&#8221; single spline crankshafts lacked: <strong>replace the hermetic plug with a vented oil filler cap<\/strong>, of the same type used on earlier Ventoux engines (some 4CV, Juvaquatre and standard Dauphine). This special cap incorporates a vent with a screen, increasing the crankcase ventilation flow. <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-9b240dd\" data-id=\"9b240dd\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-9fef741 elementor-widget elementor-widget-image\" data-id=\"9fef741\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/tapon_ventilado_interior-01-scaled.jpg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"Renault vent plug (valid for all series 4CV, Dauphine, Gordini)\" data-elementor-lightbox-description=\"Renault vent plug (valid for all series 4CV, Dauphine, Gordini). Note the peripheral holes to allow the gases to escape. \" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MjI1MjIsInVybCI6Imh0dHBzOlwvXC93d3cuamdjbGFzc2ljcy5jb21cL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjVcLzEwXC90YXBvbl92ZW50aWxhZG9faW50ZXJpb3ItMDEtc2NhbGVkLmpwZyJ9\">\n\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/tapon_ventilado_interior-01-1024x576.jpg\" class=\"attachment-large size-large wp-image-22522\" alt=\"Renault vent plug (valid for all series 4CV, Dauphine, Gordini)\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/tapon_ventilado_interior-01-1024x576.jpg 1024w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/tapon_ventilado_interior-01-300x169.jpg 300w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/tapon_ventilado_interior-01-768x432.jpg 768w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/tapon_ventilado_interior-01-1536x864.jpg 1536w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/tapon_ventilado_interior-01-2048x1153.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-3c61edf elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"3c61edf\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-8733ed6\" data-id=\"8733ed6\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-d54ba49 elementor-widget elementor-widget-text-editor\" data-id=\"d54ba49\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>With the additional vented plug, the problem of overpressure &#8211; and oil &#8216;release&#8217; &#8211; on our Gordini disappeared completely. In fact, Renault itself re-employed both vents on the <strong>Dauphine 1093<\/strong> racing version (1962-63, ~55 hp), thus ensuring maximum vapor evacuation in extreme use. Manuals of the time stressed the importance of keeping the breather screen clean and the duct clear.  <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-61c207a elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"61c207a\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-a6de99b\" data-id=\"a6de99b\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-1b7ac3b elementor-widget-divider--view-line_icon elementor-view-default elementor-widget-divider--element-align-center elementor-widget elementor-widget-divider\" data-id=\"1b7ac3b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"divider.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-divider\">\n\t\t\t<span class=\"elementor-divider-separator\">\n\t\t\t\t\t\t\t<div class=\"elementor-icon elementor-divider__element\">\n\t\t\t\t\t<i aria-hidden=\"true\" class=\"fas fa-info-circle\"><\/i><\/div>\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-83af2ee elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"83af2ee\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-2a61f88\" data-id=\"2a61f88\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-3c23292 elementor-widget elementor-widget-heading\" data-id=\"3c23292\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\"><p><b>How to check the ventilation system on a Ventoux engine<\/b><\/p><\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-4a12a07 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"4a12a07\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-df6e5bb\" data-id=\"df6e5bb\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-a84fa07 elementor-widget__width-initial elementor-widget elementor-widget-text-editor\" data-id=\"a84fa07\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>At the time it was attributed to a possible crack in the crankcase, deteriorated seals or even to an additive that had been added days before to &#8220;clean&#8221; the lubrication circuit.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-aa6b63b elementor-widget__width-initial elementor-widget elementor-widget-text-editor\" data-id=\"aa6b63b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<ol>\n<li><strong>Check the rocker cover:<\/strong>\n<ul>\n<li>Disassemble and thoroughly clean the inner chamber. You can do this with gasoline and a brush or with a powerful engine degreaser. <\/li>\n<li>Make sure that the 14 mm outlet is not obstructed by old deposits.<\/li>\n<li>If the pipe has a bend or extension, check that there is no condensate or solidified oil inside.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Check the side tube of the block (if any):<\/strong>\n<ul>\n<li>Check length and position (on 4CV: 67 mm from its base).<\/li>\n<li>Confirm that the pipe is not bent or clogged with paint, putty or dirt.<\/li>\n<li>Check for oil residues: a light film is normal, continuous dripping is not.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Oil plug:<\/strong>\n<ul>\n<li>If it is of the ventilated type, clean the internal metal mesh with gasoline or solvent.<\/li>\n<li>If it is closed and there is no other active vent that you suspect, you can temporarily replace it with a vented one to see if the leaks disappear. You can get it <strong><a href=\"https:\/\/recambiosclasicos.com\/producto\/tapon-aceite-tapa-valvulas-renault-4-4-con-filtro-respiracion\/\" target=\"_blank\" rel=\"noopener\">here (Spain)<\/a><\/strong> y <strong><a href=\"https:\/\/boutique.techni-tacot.com\/moteur\/1828-bouchon-reniflard-huile-renault-goelette-r2087-fregate-prairie.html\" target=\"_blank\" rel=\"noopener\">here (France)<\/a><\/strong> <\/li>\n<\/ul>\n<\/li>\n<li><strong>Practical test: <\/strong>with the engine idling, put your hand around the breather outlets. You should notice a soft, pulsating &#8220;knocking&#8221; sound at the engine&#8217;s rhythm of the gases coming out. If you accelerate gently, you should not notice any smoke.  <\/li>\n<\/ol>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-38c9227 elementor-widget-divider--view-line elementor-widget elementor-widget-divider\" data-id=\"38c9227\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"divider.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-divider\">\n\t\t\t<span class=\"elementor-divider-separator\">\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-12e5f4f elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"12e5f4f\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-0fdc509\" data-id=\"0fdc509\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-bb6b3b4 elementor-widget elementor-widget-heading\" data-id=\"bb6b3b4\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Technical conclusion<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-2cb1d04 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"2cb1d04\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-ec5473e\" data-id=\"ec5473e\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-44e32dd elementor-widget elementor-widget-text-editor\" data-id=\"44e32dd\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>In all engines, crankcase ventilation is not a minor detail: it is <strong>part of the dynamic balance of the engine<\/strong>.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-c23d9c6 elementor-widget elementor-widget-text-editor\" data-id=\"c23d9c6\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>If you notice significant oil leaks or drops in oil level that you are unable to explain, consider whether the crankcase breather may be the cause. Keep in mind that if there is overpressure, the vapors will try to escape through the easiest or weakest point. In our case they escaped first by breaking a deteriorated oil seal, and then through the rear crankshaft outlet.  <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-79b3654 elementor-widget elementor-widget-text-editor\" data-id=\"79b3654\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>In the case of overpressure losses, it is easy to confuse the consequences with the causes.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-35a65c1 elementor-widget elementor-widget-text-editor\" data-id=\"35a65c1\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>For Ventoux engines : A <strong>clean vented plug<\/strong>, a <strong>clear rocker cover tube<\/strong> and &#8211; if present &#8211; a <strong>properly calibrated side breather<\/strong> ensure the right pressure in the crankcase and prevent leaks without the need for additives or miracles. For any engine in your car, I suggest you look in the technical documentation because you will surely find where to do the oil sump breather checks. <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-92a99b8 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"92a99b8\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-8a21f9a\" data-id=\"8a21f9a\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-353d172 elementor-widget elementor-widget-image\" data-id=\"353d172\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"1024\" src=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ventoux4cv_a-1024x1024.jpg\" class=\"attachment-large size-large wp-image-22649\" alt=\"\" srcset=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ventoux4cv_a-1024x1024.jpg 1024w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ventoux4cv_a-300x300.jpg 300w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ventoux4cv_a-150x150.jpg 150w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ventoux4cv_a-768x768.jpg 768w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ventoux4cv_a-1536x1536.jpg 1536w, https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/ventoux4cv_a-2048x2048.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Throughout the life of the Ventoux engine, Renault adopted different solutions for the oil gas breather: from simple breather caps with a grille, to vent pipes located in the rocker cover or in the block. We will now take a look at the historical evolution of these solutions according to the engine versions. <\/p>\n","protected":false},"author":1,"featured_media":22649,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"elementor_header_footer","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[496],"tags":[],"class_list":["post-22650","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v27.4 (Yoast SEO v27.4) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>Crankcase ventilation systems on Ventoux engines<\/title>\n<meta name=\"description\" content=\"Throughout the life of the Ventoux engine, Renault adopted different solutions for the crankcase breather: from simple breather caps with grilles, to ventilation pipes located in the rocker cover or in the block. 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Here is a historical evolution of these solutions according to the engine versions\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.jgclassics.com\/en\/2025\/10\/22\/crankcase-ventilation-systems-on-ventoux-engines\/\" \/>\n<meta property=\"og:site_name\" content=\"JG Classics : The thrill of time travel\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/profile.php?id=100086454427345\" \/>\n<meta property=\"article:published_time\" content=\"2025-10-21T23:22:57+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2025-10-22T08:30:48+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.jgclassics.com\/wp-content\/uploads\/2025\/10\/pie-pagina-1024x658.png\" \/>\n<meta name=\"author\" content=\"JG Classics Administrator\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:description\" content=\"Throughout the life of the Ventoux engine, Renault adopted different solutions for the crankcase breather: from simple breather caps with grilles, to ventilation pipes located in the rocker cover or in the block. 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