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My classic car leaks oil (iV). Renault Dauphine underbody protection – Center tray

JG Classics Administrator — Fri, 15 Sep 2023 01:19:00 +0000

My classic car leaks oil (iV)

Underbody protection for Renault Dauphine/Gordini: part 2: center plate

Underbody protection central area Renault Dauphine/Gordini

As the second part of the entry“part III” of“my classic car leaks oil” that we focused on the Renault Dauphine/Gordini, I present this one with the central protection plate.

As I told you in the above mentioned“part III“, the Renault Dauphine/Gordini has completely unprotected underbody at the rear. It is curious, because in fact there is a part that is protected as standard (in our photos you will see that it is painted silver (we painted it that way at the time). But the rear part (between the center of the chassis and the “engine-differential-gearbox” assembly) there is nothing. And all the cables, rods and controls between the engine and the cockpit pass through there (including the battery cable that goes to the starter motor, since in the Renault Dauphine, unlike the Renault 4CV, the battery goes in front).

Also in that area we have another oil plug susceptible to give some “moisture”. This is the one for the gearbox. It is certainly the least conflictive, and does not usually cause problems. But since the bass is protected, the plug is also protected.

Additionally: Attention to the crankcase gas vent.

Many oil “leakage” problems can come from engine breather problems. Especially prone to happen in engines that are several tens of years old. I invite you to additionally see this article where I talk about the problem and share with you our own experience. .

Installation of protection plates, easy disassembly, and periodic inspections

This is a point that may seem obvious, but is nevertheless worth mentioning: the fact that you protect the underbody of the car obviously does not mean that it is no longer necessary to check it :-). That is why these plates, if you notice, are very easy to remove and put on and all of them are fastened with bolts that are manipulated from one side only. So our recommendation is that periodically – for example during oil changes – you check the liquid collection trays, where, if there are any leaks, you will be able to see them directly by their presence in the foam collection areas that the plates have.

The central plate

It is attached to the underside at four points:

The rear part is attached to the same brackets that hold the front part of the back plate. See here for details.
At the front, it is anchored to the cross member in the center of the chassis by two rivet nuts, as I told you in the previous part of this post of Renault Dauphine, a small wonder that allows inserting female threads when you only have access from one side, and the best, with the possibility of large tightening if necessary, such is the firmness they acquire when installed.

Rivet nuts. For fastening bolts where you have access from one side only

Here is a video from a supplier of this type of material explaining the technology of rivet nuts (they also have them in male thread format, i.e. “rivet studs”).

The tool used in this video is a compressed air tool, but there is also a battery-powered screwdriver for about 70 euros (price in Spain in 2023), which gives the same result.

This video, as I said, is of a specific supplier of this type of material, but there are many suppliers of this type of material on the market, so you will have no problem finding one in your place of residence.

Center plate: Schematic and implementation

Without further ado, here is the diagram of the central plate. The general shape (contour) is made with the base of the real template, and as it has irregular shape, to fit the underbody and especially to pass around the gas tank. You can see that the schematic includes many measurements and dimensions so that you can make it yourself.

As the machining (cutting, drilling, bending) is manual, I suggest that you make a cardboard template that you can “present” at the installation site in order to make the necessary marks and adjustments so that the metal part will fit perfectly and without problems.

Renault Dauphine - Central underbody protection plate. Template and schematic

Click on the images to enlarge or download the templates.

I leave here scheme and templates of the central plate (click on the images and the brackets for anchoring in the area below the differential. Remember that here you have the details of the fixing of the brackets to the vehicle .

You can see here the final appearance of the planks once installed. After this overview, I show you below an image gallery with the different phases of preparation.

The plates, as in the other occasions, are structurally reinforced with riveted aluminum angle, which gives them rigidity (especially for this central plate which is considerably long) and provides a frame to house a foam to retain any liquid that may fall.

Renault Dauphine - Central underbody protection plate. Image gallery

Click on each image to enlarge and see description of the process.

This gallery of the central plate is more summarized than those in Part III because many of the details are common between them. Details that you can see in the sub-galleries of part III of this post. Anyway, I leave here three of the most relevant parts:

Anchorages in vehicle

Painting

Retaining foam

For the rest of the options specific to this central plate, you can click on the photos below to get an enlarged image and :

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My classic car leaks oil (iii). Underbody protection Renault Dauphine

JG Classics Administrator — Wed, 13 Sep 2023 05:03:00 +0000

My classic car leaks oil (iii)

Underbody protection for Renault Dauphine

No drip: but we want to protect the underbody

We continue with the saga of the usual struggle of classic car owners with small oil leaks that are not serious but annoying and lead to regular debates in the technical car inspections (ITV in Spain). And besides, protecting the underbody of the car is always an option to consider.

We did a part I and a part II of “my classic car leaks oil”. At the time of publishing part II, we did not have in perspective more actions of this type, but finally we have created this part III in which we share with you the improvement works done on our Renault Dauphine Gordini. Basically, two reasons:

It is a 60-year-old car. And the oil plugs always ooze some moisture (I’ll explain why now). And we don’t want that moisture to mix with the dust in the environment making that typical accumulation of dirt so unpleasant.
It is an “all back” car, so there are a lot of wires, electrical and mechanical that “travel” along the underbody of the car. On the Renault Dauphine/Gordini, from the middle to the back it is all uncovered. And we do not want them to be permanently exposed to the elements (they have already spent many years in that situation and we do not want to prolong it any longer :-)).

Additionally: Attention to the crankcase gas vent.

It leaks oil no matter how hard you tighten the plug. One of the problems in older cars: the surface of the crankcase is "pitted".

I tighten the crankcase cap and it oozes: I change the gasket and tighten it more. It continues to ooze. What is happening?

This is one of the typical situations of old cars depending on the condition of the crankcase and/or plug: you change the oil, put a new copper washer-gasket, tighten it, everything seems to be OK, but after a few hours the plug is wet with oil. Reappraise a little. You think you have solved the problem, but after a few more hours the plug appears wet again. There comes a point where -whether or not you have the plug’s tightening specifications- your common sense tells you that you can’t tighten it any more, under penalty of damaging the plug’s thread, or even worse, the crankcase thread. What is happening to you? It is quite possible that the plug seat in the crankcase is “pitted”. Read on and I’ll tell you more.

As I was saying, our Renault Dauphine is a 60-year-old car (it will be 60 years old this year 2023, since it was built in 1963). The two drain plugs on the engine crankcase and gearbox appear slightly “sweaty”. Not dripping, but moist.

In this type of cars (not only in the Renault Dauphine we are talking about), crankcase and plug are parts with many years, so the flatness of the screw support (or of the plug screw itself) is not guaranteed at all. If the seat is conical, the situation is somewhat better, but not perfect. This is what many mechanics call “pitted metal”. The small animation above, which shows the correct state and the “chopped” state, can show you what I mean

In these plugs it is usual to use copper (or sometimes brass) gaskets. These base their tightness on the fact that when tightened and being made of a soft metal, they deform sufficiently to adapt to irregularities and seal the outlet. Both surfaces (plug and seat) are assumed to be flat and regular. So when tightened, the copper gasket deforms, filling the micro voids left in the contact between the plug-screw and its seat in the crankcase, ensuring the seal.

But if the plug (for which sometimes it is not obvious to find a spare part) or the crankcase seat are pitted, it happens that from a certain level of irregularity, the theoretical tightening to get the copper gasket to adapt to “seal”, is higher than what the thread can withstand: The plug has a maximum tightening and what we do not want is to “pass” the crankcase thread. The reasons are obvious because the costs in money, hours or difficulty to repair such a disaster are quite conceivable.

The two images I show you are the detail view of the previous animation. Here you will have been able to see better what I mean.

Teflon: Does it work? What about Loctite 55?

In the oil pan plugs, you can use – technically speaking, whether you like it or not :-)- plumbing Teflon. Teflon is a material that melts at a minimum of 200 degrees Celsius, and there are varieties that withstand up to 300 degrees Celsius. No car engine oil reaches that temperature, much less at the base of the crankcase where the oil temperature is no more than a few tens of degrees (60, 70, 80 degrees on average, or if you want to round up, to take a conservative estimate, consider 100 as a maximum). But me personally, there are times when in the case of oil, plumbing Teflon (which in fact is really designed for water) doesn’t quite work 100% – and I have to say that I have known mechanics who used it. In any case, the fact that the plumbing Teflon does not work is probably because the problem may be that it is designed to seal water and not oil. I have yet to try the Loctite 55 which ensures tightness in threads for various fluids. Someday I will try it and share the result with you. In any case, if you are interested, click here and you will find product information.

Other option: Semi-rigid nitrile rubber seals

You have yet another option: You can try (if you find the right size, which you almost certainly will) a type of semi-rigid flat gasket found in the industry. They are made of nitrile rubber, as I said, semi-rigid, which means that their deformation is controlled (more than the copper ones but less than the rubber ones) and they are impermeable to hydrocarbons, oils and even gases. As they are semi-rigid but not as hard as a copper plug, they can better adapt to deformities or roughness that may have appeared on the plug seat without having to tighten the plug screw so much. So with or without a copper gasket combination, you can still save the situation for a very economical price. I show you a link of one of them with your supplier .

https://es.rs-online.com/web/p/juntas-y-juntas-toricas/7960794

Protecting the underbody: reasons to do it

As a good “all back” car that it is, there are many cables, electrical and mechanical that “travel” along the underbody of the car. The speedometer line, electrical cables from the dynamo/regulator to the battery and frame. The throttle cable, the manual starter cable, in the case of our Dauphine, the vacuum hose for the fuel gauge, the clutch cable, the heating air hose, the handbrake cable, the shift rod, ….. And I’m sure I’m still missing some elements. In the particular case of the Renault Dauphine, these cables/rods are protected from the middle of the car forward. But from the middle to the back, they are uncovered. And it is not the best option: dust, dirt, water, mechanical aggressions (stones, curbs…).

As I already mentioned here: if in modern cars the underbody (and all its elements) are carefully protected and faired, why not do it in our classic cars, as far as possible?

Protecting the underbody of a classic car: Yes or no?

At this point we can enter again into the debate around purism/fidelity to the originals versus functionality. And once again, our opinion is that there are no “red lines” or absolute truths here. Everyone has their own point of view, and all are more than respectable. In my personal case, as I said in an entry on this WEB site, I prefer a reliable result to a result that is 100% true to reality. It is true that fairings on a bass can detract from the “authenticity” of the car. But on the one hand they are not visible, and on the other hand they are removable if properly installed. Moreover, following a similar logic, many cars of the 1960s ended their days literally devoured by corrosion and rust, but today anyone restoring a bodywork will not forego an anti-corrosion primer – the latest generation in paints – even if it does not belong to the original material of the car.

Protecting the underbody: implementation

With the Renault Dauphine we have produced two plates that go – describing it from the back to the front of the vehicle:

First plate: From the rear to the middle of the differential (a little before reaching the gearbox).
Second plate: from the gearbox to the front half of the car, just where the sheet metal plate starts, which is the car’s central protection series.

You can see later, in 9 commented image galleries, the details of the elaboration and installation, but I show you here some general views of the final aspect:

The plates, as in the other occasions, are structurally reinforced with riveted aluminum angle, which gives them rigidity (especially for the central plate which is considerably long) and provides a frame to house a foam to retain any liquid that may fall.

For the center plank, attachment to the center plank cross joist is done with a drill and what are called “rivet nuts”, a small wonder that I admit I have only relatively recently discovered, and which provide a very easy and affordable way to install a female nut in an area where you only have access from one side. And the most important thing: They can be given a significant tightening, much more than those of the “caged nuts”.

On this occasion, the fairings have been manufactured with 1.5 mm plate. Quite a bit thicker than previous cars (the Renault 4CV and the MGA which is 0.75mm thick). It is therefore somewhat more difficult to work with -especially when bending for folds-, but in exchange it is much more rigid, which is to be welcomed.

The following have been chosen for the fasteners

H-H studs for the rear side (also sometimes called “turrets”) with M6 thread
Two specially fabricated brackets are attached to two of the differential to crankcase bolts. You can unscrew them one by one to accommodate the two brackets and nothing will happen. The central fixation is shared between the back plate and the central plate. These brackets have a welded nut so that the screw can be threaded from bottom to top without having to worry about holding the female nut.
Two self-riveting nuts at the front for the center plate. They are very easy to find on the market and the device for riveting these nuts costs about 70 euros.

Rear tray and center tray

The project, therefore, as you have already seen in the general photos above, comprises two trays .

A rear one (covers the area of the crankshaft pulley, crankcase, and its junction with the differential).
A central which covers the rest of the differential, gearbox, gearbox control rod, clutch and throttle cables, and the entire center-rear area of the chassis. -This one can be found here –

In this particular post, I provide you with detailed photos of the entire process for the rear tray. I also give you information and measurements and dimensions for a Renault Dauphine. . They can serve as a reference, but I recommend that you build yourself a rigid cardboard template, which you can adjust and on which you can mark the holes and make corrections easily.

As the process is quite extensive, I have subdivided it into different sub-galleries of images so that you can read it more easily. You can click on the buttons at below to navigate from one to another.

The following gallery contains the information for the back plate. For the central plate, here you have the entry .

Renault Dauphine - Rear underbody protection plate. Image galleries

Click on the buttons below to go through the different stages of the process.

00 - Schematic diagram of plates and brackets for anchorage

01 - Initial preparation: cutting and drilling

02 - Angles and inner structural frame

03 - Mechanization completed

04 - Turrets and holes for plate fixing

05 - Painting. Priming and lacquering

06 - Prepare under vehicle anchorages

07 - Oil collecting foam packaging

08 - Final installation on the vehicle

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Renault Dauphine braking shudder. Correct shoes

JG Classics Administrator — Sun, 02 Apr 2023 18:23:10 +0000

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The car shakes when braking (Renault Dauphine)

The situation: Renault Dauphine was shaking under braking.

The mystery of the shakes when braking seems close to being solved. The car didn’t brake badly (considering what can be expected from this vehicle), but it was shaky when braking, especially at the end of the pedal way. It was not a serious situation – it was not even detected in the ITV – but it was uncomfortable.

Diagnosis

A few days ago I discovered that the brake shoes are 30mm wide (first Dauphine model) while the drums in this unit accept 35mm wide brake shoes (second Dauphine version). I was able to verify this based on documentation I found comparing the width of the drum “track” Vs the size of the brake shoes. In fact, a part of the inner “track” of the drum is clearly unused (unfortunately, I have no pictures of them, because the drums have already been through the grinding shop machine).

In the following photos, the 30mm brake shoes are still mounted. You can see the gap they have at the bottom (see in the pictures the circles marked in red, click on the image to see it in detail). One of them shows how it can be moved with a screwdriver “in” and “out”. This gap-displacement, which is very easy to imitate with a screwdriver, is expected to happen when the cylinder pushes the brake shoes. Besides that, as I mentioned, the drum had (prior to grinding) a part of the track that has no shoe scuff mark.

The solution

I have been able to locate 35mm wide brake shoes at CIPERE (a Franco-German supplier). Additionally, the drums have been delivered to the shop for grinding (fortunately still within the tolerance margins stablihed by Renault for the Dauphine’s which is 229.2 mm for the maximum internal diameter after grinding).

I will mount in a few days the new brake shoes and repaired drums. I am almost convinced that the larger contact surface, the brake shoes of the correct width, and the repaired drums will improve braking dramatically and the problem will be solved. I actually had this experience in another car a few years ago.

Where to buy them?

New brake shoes can be found at CIPERE. They are not very cheap, but it is true that there are not many alternatives. For the Dauphine, brake shoe linings are available, but complete brake shoes are not easy to find (contrary to the Renault 4CV where complete brake shoes are very easy to find from several suppliers). Click the link below if you want to go to the product (or here).

https://www.cipere.fr/fr/Renault/Alle/Vorderradbremse-ohne-Hydraulikteile/ANR84226/

This is a situation I have encountered on many old classics: Poor maintenance that was done to classic cars many years back and once discovered, and resolved, causes the situation to be fixed almost by itself. In future posts I will tell you as an example about the OVERDRIVE of an MGB that came back to life with only proper maintenance.

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My classic car leaks oil (part ii)

Javier Guevara Vico — Fri, 23 Dec 2022 03:15:19 +0000

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My classic car leaks oil (ii): Solutions

What do I do with my oil leak?

Oil leaks are one of the usual headaches for classic car owners because the reasons that I mentioned in the previous post. previous post.

If you haven’t read it yet, you can have a look:

Mi coche clásico pierde aceite (i)

Initial Consideration: Important

I specified it in the first part of this article, but I consider it essential to insist here as well: I am talking about external and slight losses, which in many cases of old cars, are inherent to the design of the vehicle itself. Only those types of losses and no others. Large leaks, or internal leaks due to lack of sealing of rings, cylinders, pistons, problems in valve seals, cylinder head gasket and any leak that compromises the proper functioning of the engine, this is ANOTHER THING and if they happen, it requires intervention in the engine by a qualified professional.

Additionally: Attention to the crankcase gas vent.

If I’m at the point where I can’t avoid oil loss, but it’s clear to me that oil loss is not a problem, or even more, it’s part of the native design of my car, why not simply go for a permanent built-in-car device to pick it up for me instead of having to resort to trays, mats and other external resources placed on the floor?

In fact, this idea is not a “sudden” invention of mine: One day, while changing the oil in a last generation BMW (actually, now it’s a pre-last generation -it’s an F30-) I realized that the fairing that completely covers the underbody of the car is -among other things- a perfect barrier for any -small- liquid leakage. It is true that this fairing is there to cover some other functionalities, both mechanical protection of the elements and aerodynamic – to avoid swirls and air turbulence in the underbody of the vehicle. But e fact is that if that vehicle had a small oil leak, the fairing would totally prevent that oil from rushing to the outside.

Standard solutions

On new cars: Here you can see the underbody fairing on a new generation BMW.

Regardless of its function, it is clear that it will act as a barrier against any small leakage, preventing it from generating a source of contamination outside the vehicle.

For antique cars: This stainless steel part is a current market standard sold in the United States. Versions for MG and Ford engines are available.

It’s -obviously- not an underbody fairing, but it does what it’s designed to do: collect the oil that goes out from the rear of the crankshaft and drains through the gearbox bellhousing.

Creation/installation of an oil pan

This is precisely what we have done with two of our cars. Both the MGA and the Renault 4CV suffer from this circumstance. They both drip/ooze/sweat (use whatever euphemism you prefer) oil.

In the case of the MGA I am 100% sure that there is no ring seal at the rear output of the crankshaft. On the Renault 4CV, I’m honestly not sure because there were several production series of that engine in those years. In the case of ours, it is the second version of the 1950 Renault Ventoux engine, and it is possible that it does not have a seal at the crankshaft pulley outlet. In any case, even if I carries it, and I can replace it later, at this time I prefer to ensure the total absence of oil drips.

In our case, we have created the tray from ordinary 0.6 mm steel sheet. It is not a very thick one, but it has the advantage of being very workable. It can be easily bent, cut, drilled and shaped.

Structure of the oil pan

To give it rigidity, we have reinforced it with ribs made of aluminum profile and fastened with rivets. This will void you to have to weld in case you don’t have welding equipment or simply don’t know how to weld (welding in a “clean” way over a steel sheet without piercing it requires some experience):

We have chosen ordinary steel and not stainless steel for ease of painting. In our case, we wanted to install a tray that would be aesthetically integrated as much as possible with the underbody of the car and would not be an element too “visible”.

Painting

For the painting, we have given a coat of primer “Beissier todo terreno” black color (it is water-based, and has a very high adhesion power on any material, in another article I will talk about usable paints). This is from Spain, but fr sure you will find something similar in your country/area. I strongly recommend that you apply a coat of primer because if you use aluminum profiles in the assembly, the direct paint does not adhere very well on this material.

Then we applied satin black polyurethane lacquer. Titanlak from Titan, although it is a “domestic” range paint, has an excellent quality, and if left to dry for the right time (it takes at least 4 days to reach maximum hardness) it is extremely resistant.(again, your local dealers in your country will be able to provide you similar paint type if you want to use it)

Applying the paint with an airbrush, will provide you an excellent result, which is completely integrated in the underbody of the vehicle.

Final structure and foam to retain drained oil

Around the area where the oil “falls” into the tray, you can see that we have built an angled aluminum profile frame (1 cm x 1 cm): With this we achieve two things:

The tray acquires rigidity (as already mentioned).
We have created a frame in which we will house a foam sheet or any absorbent material.

This foam is replaceable, so that after a while, simply unscrew the tray, remove the stained foam, take it to a clean recycling point for oil residues – please do not throw it in the domestic waste – and replace it with a new one. Since the temperature of the oil falling in this zone is relatively low (no more than the temperature of domestic hot water), this foam more than fulfills its purpose.

Final installation

Once installed in the vehicle, we can see that it is perfectly integrated in the underbody, fulfilling its task and preventing any drop of oil from falling to the ground.

Maintenance is very simple. the tray is fastened with four screws (two on each “wing” of the tray). From time to time (e.g. every oil change) it is very easy to disassemble the tray, remove the foam, dispose of it at a clean recycling point, and replace it with a new one.

Renault 4CV Tray - Phases and details

Here you can see a small photo gallery with the different phases of the manufacture of the tray oil pan of the Renault 4CV. These are just a few images, but I hope they give you enough ideas to get you started if you want to do something similar. I also give you some details that I think may help you:

The paint, as I said, is applied with an airbrush. The primer is water-based, while the lacquer is solvent-based. You don’t need an expensive airbrush, but much better a good air compressor that gives you a sufficient flow for your paint airbrush. In any case, it is not “so critical” painting task. But if you apply it with an airbrush, the result will be much better. Alternatively you can use a spray, but sprays are expensive and generally use more paint than necessary.
To cut the iron sheet, you can use one of those miter saws that carpenters carry when they go to assemble doors in a house. Although they are made for wood, there exists in the market the so-called “multi-material disc” that fits these saws, with which you can cut iron and aluminum sheet (I discovered it recently and I was amazed at the good results with metal). The straight cuts are perfect, the miters are 45 degrees, the squares measure exactly 90 degrees, you can make symmetrical oblique cuts at the angle you need, etc, etc, etc. Nothing to do with hand or jigsaw made cuts. Miter saws are available in many price ranges, but you don’t need a 600 euro miter saw. If you decide to buy one, I do recommend that it has longitudinal displacement: the possibilities of use grow exponentially (they are also called “telescopic miter saws”).
Working with iron parts and machines: That’s a combination to be respected. Please, always anchor the pieces very well with suitable jacks or clamps, and do not rely on your hands to hold them while they go through the drill, the polisher, and much less through the saw. A piece of metal flying off can be the cause of a very serious accident – I don’t even want to imagine a direct accident caused by a saw with the power of a miter saw. My personal advice: invest time and resources securing the work environment and work on the premise of “zero risk”.
Bad riveting machines are major time wasters. The ones with a certain quality are not very expensive, and are well worth it. I would say, run away from these“riveter+kit 300 rivets for 12 euros” promos.
Should you have someting else that you would like to know or any other details you would like to see, please feel free to write me in the comments or contact us directly and we will be happy to help you.

Click on the images to see the comments

Other examples of users who made similar things

I give you some references of owners who have adopted this solution on classic cars: These are for MGA from UK and USA users.

https://mgaguru.com/mgtech/engine/cs212.htm

https://mgaguru.com/mgtech/engine/cs213.htm

https://mgaguru.com/mgtech/engine/cs214.htm

Oil pan on our MGA (engine and transmission)

Here you can see what we did in our MGA: In this job, oil collection has been extended all the way along the driveshaft. In this car the driveshaft is uncovered, so that in addition to safeguarding the oil drip, we provide protection against dust, or blows from stones or foreign objects. Here the tray is painted in black and red, matching the color of the car’s underbody and the color of the MGA engine oil sump.

Conclusion

As I told you, the idea to manufacture this small device came from three different sources:

The oil mat that I told you that some suppliers provide.
The noticing that all modern vehicles have the under-vehicle covered by a fairing, and therefore, small oil drips are retained by the fairing and avoid staining the environment (besides other functionalities that the fairing may have).
Works exposed in (among others) the links mentioned here above about an EGM.

Finally, I will insist once more on the point I mentioned at the beginning of this article: This proposal is only for small external oil leaks in which the elimination is not feasible due to the difficulty of obtaining spare parts/labor, or because the leak is inherent to the design of the engine (because it is very old and does not have oil retention elements). And above all, that it does not compromise the proper good working of the vehicle.

Still, if you are not really sure and have doubts, I advise you to have the car checked by a professional who will make a complete diagnosis and give you a proposed resolution adapted to your car. If you still want to share your situation with us, you can contact us and we will gladly give you our opinion, regardless of the solution you may finally decide to adopt.

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My classic car leaks oil (i)

JG Classics Administrator — Tue, 20 Dec 2022 17:37:13 +0000

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My classic leaks oil (i)

This is a situation as frequent as undesirable in classic cars (actually, in non-classic cars, when they are a certain number of years old, also). These oil leaks are called in several ways, with more or less degree of euphemism, but at the end of the day, they drive to the same thing:

Oil leak
Little oil drops
Oozing oil
Sweat oil
..

Initial consideration. Important:

Here I consider it important to precise something: I am talking about external and slight losses, which, in the case of many old cars, are inherent to the design of the vehicle itself. I am only talking about those types of losses and not other ones. Large leaks, or internal leaks due to problems of sealing around rings, cylinders, pistons, issues in valve seals, cylinder head gasket and any leak that compromises the proper functioning of the engine, this is ANOTHER THING and if these issues happen, it requires the intervention of a qualified professional.

Additionally: Attention to the crankcase gas vent.

These external oil leaks that I mention here – even if they are slight – have two consequences:

They are smearing wherever the car parks or passes by.
They can give you problems in the ITV (technical inspection cerification) at least in Spain.

The first consequence has a direct interpretation: we like classic cars and historic cars, we are passionate about automobiles. In general, we like mechanics and “tinkering”, but we don’t like to mess up or polluting the environment. No need to mention that industrial and automotive oils are one of the most polluting wastes that exist.

As for the second one, the problem is that it has an interpretable reading: In the MOT inspection, “oil leaks WITHOUT dripping” are a minor fault, but “oil leaks WITH dripping” is considered a major fault (at least in Spain) and generates an NON-PASSED INSPECTION. And the discussion lies precisely in what is understood as “drip” and what is understood as “non-drip”. In reality, any leakage of a fluid implies dripping (unless the fluid solidifies or gels spontaneously, but this is not the case with oil, at least not at the “ordinary” temperatures of our climate). So it’s all a matter of “how soon” the trickle down occurs. It is therefore at the discretion of the MOT technician to determine whether we are dealing with a “drip YES” or “drip NO”. And this, in the MOT inspection, in many occasions, is usually a source of debate/dispute or at least in an uncertainty about the result of the report.

What can I do to resolve this oil leak?

This is where the problem often comes: The MOT inspector technician will probably explain to you where the leak is coming from and you will probably hear a phrase such as “.you would have to change the seal/gasket of XYZ …” -this is usually most of cases-. And here, if you want to solve the problem, you can find yourself – in general – with several options, which finally will drive you to one of two possible situations: The replacement of the responsible part is feasible or not:

Situation 1: replacement of the sealing element (gasket, seal, plug, etc.) is feasible.

- First option: it is a gasket(external, I insist once again, I am NOT talking -for example- about a cylinder head gasket) and the replacement is feasible. A flat gasket, even if not commercially available, is easy to make, and in most cases is usually replaceable with reasonable effort. It is true that in some cases, such as the oil pan or sump gasket, it is usually necessary to lift the engine block because the front or rear axle (depending on the location of the engine block) prevents the sump from being removed. But in any case, we are talking about assumable effort.
- Second option: It’s a seal ring and you can change it with reasonable effort. Spare parts are available and labor is affordable in terms of time and effort. Some of them may require you to remove parts that generate more work, such as a crankshaft pulley, or a water pump that prevents you from getting to the oil seal, but again, we talk about something that can be addressed at a moderate cost.

Situation 2: The replacement of the sealing element is unaffordable or of an unaffordable cost.

- The oil seal replacement is not feasible, either for one of the following reasons:
  - Not available on the market
  - You cannot afford (economical labor cost effort) to change it.
  - It never existed: that model simply did not have a seal. It is not present in the original car design.

NOTE: What I have presented here so far is a generalization and obviously there may be many other particular cases, but the reality is that in most cases, the situation will be very similar to one of the ones described above.

I am in situation 1: I can replace the part at an affordable cost.

If you are lucky enough to be in situation 1, my advice is not to even think about it: Go for the direct replacement of the sealing element: No intermediate repairs, no “miracle” additives that promise to restore the sealing where there were leaks before. I have never seen anyone that worked.

If you replace the part, it is true that you will spend hours and/or money (more hours or more money depending on how much you do yourself or how much you ask a professional to do it), but it will have been an assured investment. If you also consider the fact that you are doing it with a classic car, and therefore the few kilometers it is likely to do per year, it will probably be the last time you replace that part. And the problem will belong to the past.

I am in situation 2: There is no sealing element in that part (or there is but it is not affordable for me).

You may also find that even if a replacement is available on the market, the cost of replacement is unaffordable for you at the time. These parts use to be inexpensive, usually costing no more than few euros/dollars/pounds/,.., but some of them may take maybe 10 hours of labor to be replaced (and may need special tools such as extractors, press, etc.).

And finally, it may be that your car simply does not have any kind of sealing element at the oil leak point. This situation happens in many older cars and for some types/brands: it’s a known situation. In the same way that many old vehicles (I am talking about 1960 backwards) did not have fuses in the electrical installation, they don’t also have any oil ring seals. They did not exist at that time when car was manufactured. So don’t look for them: there aren’t any.

Really? Isn't there any kind of seal ring?

Really. Many of the old cars did not have any at the output of the different shafts (crankshaft, cam, secondary shafts, etc.).

In reality, even when a seal ring exists as a engine part for many years and it may look simple, it’s not at all a simple element to manufacture or design.

A seal ring is a sealing element (let’s colloquially call it now a “gasket”), in the form of a ring (or sometimes a cylinder), which is installed in an orifice in a fluid-filled recipient, an orifice through which a moving part (a rotating shaft or an oscillating axe, as in the case of valves) “comes out”. And its mission, as the name suggests, is to “retain” or “seal” the fluid so that it does not escape. As the outgoing part moves (oscillates or rotates), this “gasket” must be elastic enough to allow the movement of the part (usually a shaft, as I said) but tight enough not to allow the fluid (usually oil) to escape to the outside.

In this link you will see a very didactic scheme. If you are not familiar with the technical details, I recommend that you watch it.

When desgined, the engineers balance between several circumstances to achieve their goal:

With the material (having the appropriate level of plasticity/elasticity).
With auxiliary adjustment elements (such as a small spring surrounding the rubber ring).
Shaped so that the “push” of the fluid that wants to escape “deforms” the part so that it fits, “tights” and insulates correctly.
They may also have splines in the inner wall of the ring that redirect the fluid to prevent it from escaping.

Seals and their manufacture: Although it is a cheap part -because they are manufactured in large quantities in a highly industrialized way-, their conception is not at all obvious or trivial. I show you a website of a manufacturer of oil seals, where explanations are given in great detail and very illustrative and didactic schemes: You can see this link (Sabó Retenes)

Retenes

At the time when there were no oil seals as we know them today, one of the oil retention systems in the axles of many old cars was a piece at the end of the axle, which had been machined a spiral, as if it were a drill: When rotating, the spirals tended to “pull back” the oil that “wanted to get out” by pressure. In other words, like a grinder that was forcing the oil to re-enter the inner area of the engine (or transmission): in the same way that the twist of a drill bit expels the drilled material “backwards”. In this link you can see the axis of an MGA with the twisted spiral that I mention. You can see it on the right side of the image. By the way, besides the image itself, and the observation of it, the article in the link is very interesting.

https://mgaguru.com/mgtech/gearbox/gt201.htm

One of the costraints or inconvinients of these systems is that they operate only while the engine is rotating. But when the engine stops, this “turbine effect” stops and for a few moments some oil may fall outside, even if there is a cover or supplement to prevent this from happening. It is inherent in the design.

Drain holes: In many classic cars this behavior was so assumed that it is common to have some oil drain holes to prevent the oil from accumulating in some areas adjacent to the leak – where it could cause problems – and therefore ensure that the oil is completely drained to the outside. A typical example is the rear output of the crankshaft or the input of the primary shaft of the gearbox. If oil comes out of one of the two places – from the engine or the transmission – the last thing we want is that it accumulate inside the gearbox bellhousing, since the clutch is located there and if the clutch disc is stained with oil, clutch will no longer work and will remain unusable. Therefore, oil must never be accumulated inside the unit so imperatively needs to be evacuated.

Here you can see it in detail:

I show you another example: Here is a 1956 Renault rear axle. You can see the hole drilled so the small oil leaks coming from the transmission -differential and gearbox, in this model the oil sump is common for both elements- comes out, and does not remain trapped inside, which if it happened, could cause oil to reach the brake area in the other side of the axle, which, for obvious reasons should not happen. You can see that in this hole there is also a small steel ring as a key to ensure that it does not clog (Renault 4CV, 1956).

Oil-collecting mat: In English classic cars (MG, Austin Healey, Jaguar) this situation is so common that there are suppliers that sell trays or mats to collect the oil under the car when it is parked.

https://www.limora.com/es/esterilla-antigoteo-de-aceite/355878/

What you see in the image below (on the right if you see it on a computer and below if you see it on a cell phone) is the “bell” of the gearbox of an MG: it has a small hole that is precisely to drain the oil coming out of the crankshaft, and prevent it from staining the clutch disc. This hole usually has a small plate (key) that, with its movement due to the vibration of the engine, prevents the hole from clogging and therefore could prevent the oil from escaping. You can see the general photo with the drainage hole on the right side of the photo (the drainage point is circled, click on the image).

What about the MOT inspection?

Well, as I said, the MOT inspection can be a problem. Please, note that the MOT technician has a procedure to follow. And in his/her procedure, if they inspect a vehicle which shows oil leak, they are obliged to issue an UNFAVORABLE/NON-PASSED report (regardless of their personal opinion, or no matter if they are are familiar with these types of cars and designs, which may or may not happen).

Possible options

Inspired by ideas that other users have put into practice, in some products that have become standard market ones for some models, and also in the engine low covers that come in modern cars, we have managed to solve the problem in a couple of vehicles with a solution as simple as collecting the oil in an integrated way in the vehicle, so avoid any dripping.

I invite you to watch part ii of this article .

I hope that our solution can help you and/or be useful for you as idea or starting point to elaborate your own one.

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La entrada My classic car leaks oil (i) se publicó primero en JG Classics : The thrill of time travel.