Hi all, I have a 1994 facelift XJS 4 litre which has been stood idle for a while. On restarting there is smoke coming from the exhaust manifold on the right bank nearest the driver that isn't burning off. Anyone had a similar issue or can suggest a solution?

 

Firstly welcome to the Forum.

Please do an Intro in the New members Area when time permits.

The camcover gasket and the 2 "D" seals at the rear are the most common oil leakers on the AJ6/16 engines.

 

I recently posted a similar issue with my '94 AJ6 XJS, if you check recent XJS posts. Your leak location appears to be the exact same as mine. In my case, when the manifold is not hot enough to burn off the oil it drips to the floor. Then, it warms up and the smoke begins. The bottom of my exhaust manifold shows oil humidity on it and I've checked the back end of the cam cover seal area (which is obviously at a level above the exhaust manifold) and it is dry, no sign of oil. So, where is the oil coming out? Have you checked the rear of the cam cover seal area for presence of oil? If your is dry as well, then we both seem to have the same problem. I mean, BIG difference between having a cam cover seal leak vs. a head gasket leak $$ wise.

I wonder now how common this problem really is, perhaps at the turn of 100K miles? All of a sudden there's mine and yours. Then, I was just reading this article advertising their "Half Moon" seals solution and it sure seems like this is the same as what Grant Francis was referring to as 2 "D" seals. This is what they say:

"The Jaguar V12 cylinder heads (and the AJ6 inline-six cylinder head) have a couple of cuts in them generally referred to as half-moons. The plugs intended to seal them are squashed in place with the cam cover gasket, making for a really lousy seal. The end result is that sooner or later the half-moon is going to be the source of an oil leak". -- Then they go on explaining how their device resolves the leak.

"What you get: One half-moon seal with Viton sealing strip".
"Why you'd want it: No more leaks from the back of the cam covers. Ever".

If this prevents a cam cover seal leak, then I don't believe it will resolve my problem, since my seal is dry.

This below is their illustration, I'm not familiar with this, myself.
Other than that, it's disappointing that only a single person (Grant Francis) seems to know anything about this issue.
Cheers!

 

Agreed.

I use RTV Red Hi Temp on the AJ16 (Integral D Seals), and the AJ6, (seperate D Seals), with no leaks at all.

Copious amounts, wipe off "squished excess"with solvent soaked rag withing 10 minutes of fitting.

Same on the V12.

"D" = Aussie for half moon. ha.

 

[QUOTE=Grant Francis;1720342]Agreed.

I use RTV Red Hi Temp on the AJ16 (Integral D Seals), and the AJ6, (seperate D Seals), with no leaks at all.

Copious amounts, wipe off "squished excess"with solvent soaked rag withing 10 minutes of fitting.

Same on the V12.

"D" = Aussie for half moon. ha.[/QUOTE

This job is pretty much like the above mentioned D seals repair to stop a cam cover seal leak, correct? Only problem is that the leak I have doesn't seem to be coming from this source because upon inspection, my cam cover seal joint seems to be fairly dry, but I'll check again. Otherwise we're still searching for that mysterious oil path...

Thanks for the info!