Is there an underlying problem if oil is leaking or will replacing valve cover gaskets be sufficient in solving problem. 86 xjs

 

Firstly welcome to the forum.

When time permits, please do an intro in the "New Members Area".

No underlying issues, apart from the huge amount of work to do them.

I would ensure you also get, and replace, the 2 "D" seals at the rear of the tappet blocks. I liberally smear them with Hi-Temp RTV, and have had no failures ever.

Renew the fuel hoses, and by that I mean ALL the fuel hoses.

When you get the new gaskets DEMAND the new style Gortex type gaskets. DO NOT fit the old style cardboard/paper gaskets, they will leak.

When you lift those inlets off, plug the 12 holes real fast, coz that odd whatever WILL drop in them in a heartbeat.

Count your washers/nuts/bolts/etc, and move ALL the loose stuff well clear of the engine bay BEFORE lifting those manifolds. You will be a very sad Jaguar owner if it "knocks" on restart, and you realize where that missing washer is. Been there a very long time ago, still got the pain.

 

As Grant said, be sure to replace the half-moon seals at the rear of the tappet block. They are the single largest source for oil leaks at the top of the motor. The holes that those seals fill serve absolutely no purpose on the motor. They were necessary as part of the milling process, and Jaguar didn't engineer a very good solution for sealing them.

Because the original half-moon seals are made of rubber, the heat breaks them down over time, and they fail before the cam cover gaskets do. You end up with oil pouring down the back of your motor, and onto the hot exhaust. To avoid that on two of my V12s, I permanently filled the holes with JB Weld on one motor, and I purchased aluminum half-moon seals for the other. I still need to replace the seals on the 3rd motor, but, for the moment, the effort to do so far outweighs the benefits for me (in other words, I'm just too lazy to be bothered with it right now).

As for the cam cover gaskets, make sure you get the gortex gaskets, which Ford designed when they owned Jaguar. For the right side cam cover you want P/N EBC 9628 and for the Left cam cover, you want P/N EBC 9627.

 

Hi, I saw this thread when I was looking for an answer to my question. I have a 94 Jaguar XJS 2+2 Convertible with a 4.0 engine. Someone told me that when I replace the valve cover gasket to only use a genuine Jaguar OEM replacement and not an aftermarket. I purchased a genuine Jaguar gasket today through Coventry West but I don't know what material it is made of. I should receive the gasket before this weekend. My question is this. Do I need to use gasket sealer on the gasket? The last time I did this was my old 56 Chevy a long time ago. Then I used gasket sealer on both sides of the gasket. I think it was made out of cork. As I stated I don't know what the original Jaguar gasket is made of and I see on Google that some people say not to use sealer on gaskets any more. Please give me some advise on this. Thanks, Bob.

 

The AJ16 has a different style valve cover and a rubber gasket like a lip with integrated halfmoons. No sealant required at all. But you can put a dab on the head first if you want.

 

Thanks. I have the earlier AJ6 4.0 engine. I don't know if it is rubber or not at this point. I would rather not use the sealant if possible but I want a good seal. Thanks, Bob.

 

I use a pan when performing surgery. From small to large dependant on the task. All the tools, fasteners and smallish parts go in it. Much less strays that way.


Carl

 

Received gasket today. It is rubber so I don't plan on using a sealant. Thanks, Bob.