Hi All,

Where should I start looking for the leak(what's most likely)? Engine oil gets onto the (I guess left side) exhaust pipes. I read in Kerby'sbook that it is unlikly to be the rear main seal. What is the most likely source?

 

My car has a very slight leak out of the A-bank (passenger side) head gasket which dissipates/evaporates quickly as it drops on the hot exhaust pipe. After the car sits for awhile it usually takes a few minutes for the slight smoke to clear, but I can live with that. My mechanic says it's very typical and nothing to worry about. Also says its a PITA to remedy. How much oil is leaking onto the pipe?

 

Greg,

I am going waaaaaaay out on a limb here and assume you have a V12????.

If so, my suggestions in order of frequencies from my experiance.

Look at the 2 oil sender units at the back of the "V", THEY LEAK, usually the smaller one, which is for the light, and the oil runs around until it finds it way out of the area, done the casting and onto the pipes.

The rubber "D" seals in the rear of each camblock shrink and leak, PITA, but it happens.

The oil filter, OR the housing with its associated o/rings, and bleed off hoses.

The banjo bolts in the rear of each camblock sometimes leak, but be CAREFUL, the threads will strip if attacked too hard. This is a rare leak area, but it does happen.

 

Thanks all. Assumption correct (V-12 - implicitly in my posting it being a V was included ) More precisely, a 1989 V-12 with Marelli crap

 

just how unlikely is it to be those banjo fittings???

because mine is leaking onto the passengers side cat and burning off.
Its rather embarrassing pulling up to lights with smoke pouring outta the bottom of the car.

I was first thinking it was the valve cover but then I found out about the banjo there.

Its a pretty steady amount of oil. It isn't dumping, cat will keep up, but Im afraid it it lighting on fire or something. and I hate having a leak.

just got a license plate 3 days ago, loving it so far

 

As I said the banjo leak is NOT common, but the "D" seals just above the banjo's are as common as V12's loving fuel, mmmm.

It runs out of there quite freely if the seals have shrunk sufficiently, which they do, and down to the banjo giving the appearance of the banjo leaking, which as I said is rare. Also the banjo oil is under pressure, 80+psi, and would empty the sump quite quickly. The "D" seal oil is NOT under pressure, it is just a leak from the inside to the outside, and yes it is quite messy, and always looks worse that it really is. A small amount of oil spilt looks bigger than it actually is, and when it causes smoke, is worse again.

The "D" seals require the removal of the camcovers to execute, and that is not a 5 minute task by any means.

 

BUT.....

Since so much has to come off, including the inlet manifolds, it's an outstanding opportunity to clean the vee, replace fuel and vacuum hoses, repair wiring, replace spark plugs, etc.

I say "manifolds" plural because it would be a shame, IHMO, to reseal only one cam cover at a time.

Cheers
DD

 

im sorry but im not exactly sure what you are referencing. the only thing i see above the banjo is the cam cover, are you talking about that gasket or something different?

 

You cant "see" much there, or at least I cannot, it is partly visible I agree.

Run your finger up above the banjo, about 10mm, and you will feel a "half moon" shape. Thsi is the "D" seal, and originally was nice and soft, and now as hard as the surrounding metal, there is your leak, the "soft" rubber has shrunk, oil comes out.

Above that "D" seal and directly below the nice looking finned cover is the gasket, and oil will come out of it as well at the area where it goes over the "D" seal, shrinkage again.

The camcovers need to come off to replace the "D" seals, and the gasket, and the inlet manifolds need to come off to get access to the camcovers, and the fuel rail needs to come off to get at the inlet manifolds easily, you follow the sequence so far. It is a good days job if you are familiar with the process, and a good weekends work if its your first time, but always FUN.

There will associated items that will need attention, fuel hoses, vac hoses, injector seals, and a loooooong list of minor items depending on how fussy you are with your car/engine bay. Unfortunately it is NOT a quicky repair, sorry, but we have nearly all been in there with our cars, and it is not that bad in the general scheme of things, but annoying if you have only had the car for a short time, but once done, and done PROPERLY, it will last another 10+ years.

 

Tje valve covers tend to develop slow leaks. Mine happens to be on the front right bank. It's annoying, but not a fire hazard. I have also had to replace my front main seal way back when. The valve covers are a pain to get off so unless mine starts pumping more oil onto the exhaust than BPs deep sea oil head I'm not going to bother replacing the gasket.

 

wow this leak is now getting oil onto my alternator belt and make it slip at idle.....ARGH

 

If you are getting oil from the "D" seals on the alternator belt, YOU GOT SERIOUS ISSUES, the engine that is, not primarily yourself.

The most common "oil on alternator belt" is from the "rubber" plug in the timing cover used to "set" the timing chain tentioner on refit, on the RH side of the front face of that cover, and like the "D" seals, goes hard, and shrinks, and LEAKS.

Are you positive that the engine breathing system is working at all, coz this is getting more and more like an engine that is unable to breathe.

I know you have stated that your knowledge is limited, OK, but if you run the engine (idle only) with the oil cap off (OK you are going to get a little oil splash), and with engine idling, is there any "pressure" coming from that opening, hold your hand sort of over/near the opening, you really should NOT feel any air "pumping". There are more sofisticated ways of testing it, but this is a very basic way of getting a feel for the engine itself.

We all know these engines leak oil from rather specific places from old age and a little bad design, but generally not in the volume that you have been describing.

Not sure where you are in the world, but surely there is a Jaguar workshop, maybe not a dealer, somewhere nearby that could give you a decent steer as to what is actually causing all this oil to apparently "flow" out of the engine in what seems odd places.