My mechanic has replaced the valve cover gaskets on my 2001 XK8 three times, the last time being less than 2000 miles ago. The left side is leaking again. Is this a common issue with the 4 liter engine, or is there a secret to getting a seal that lasts?

 

A lot of people will argue against it but I had the same issue with my 2000 XK8 and when I replaced the valve cover gaskets I used RTV sealant. I am not talking about using sealant to make a gasket but to use enough to insure against leaks. You must use sealant in two places on each gasket. I used sealant lightly on the entire gasket and no longer have any leaks. Of course you must allow time for the sealant to cure, torque to specs and tighten with the correct pattern.

Good luck.

 

The most likely reason for the leaking is that the part load breather is plugged. You need to remove the part load breather hose and with a small drill bit clean out the orifice in the cam cover fitting.
A plugged part load breather will pressurize the cam cover and no amount of sealant will stop them from leaking. Give iit a try, it is a simple procedure.

 

Another cause of leaking is hairline crack(s) in the covers from overtightening. These are usually undetectable when the cover is off and only open up sufficiently to leak once it is refitted.

Graham

 

What do you mean must use sealant in two places? You mean on both sides of the gasket. I have this problem -- left cover -- and it's very aggravating

 

The 2 places that the shop manual shows as placing a dab of sealant is at the location on the cylinder head side where the timing chain cover and the cylinder header join. The rest of the gasket surface is just cleaned and no sealants,

 

Yet another possibility is the isolator washers (NCA2575CA). These are meant to apply the appropriate pressure to hold the cam cover snug to the head when the bolts are torqued down.

They're in an ideal place to bake over time and don't always get renewed since OEM replacements are around $3 each, and you need 28...

 

This how I did my valve cover gaskets and the last photo shows where you need to put the sealer.

Link JagRepair.com - Jaguar Repair Information Resource

I hope this helps

 

Thanks for all of the suggestions. The part load breather fix appears to have worked. I no longer have a burnt oil smell.

 

interesting, in the TSB's there is a cutoff by either year or vin for servicing the part load breather, partway through 2001. is it something that should be cleaned regardless of year in the membership's experience?

 

My mechanic things the left side valve cover on my 2001XK8 is warped. A new Jaguar part is very expensive. Will the comparable Ford/Lincoln part work, or any suggestions on finding a used cover?

 

He thinks it's warped? Placing it on a flat surface like a thick sheet of glass should determine that. Cracks are certainly likely. I suspect your mechanic may be wanting to throw parts at the problem.

 

I am tempted to try one more replacement before spending at least $300 for a new valve cover. I don't know if warping is a common problem with the plastic covers, and I don't think my shop checked for that issue when the gasket was changed the last time.

 

I wouldn't be surprised if you could find a cheap used cover to replace a warped on.

There are plenty of these engines across various models, and sure it would be a risk to go used, but they're surely out there.

 

I have found some used on e'bay, but they look rough. The warp issue is a guess because the cover keeps leaking. I ordered a gasket kit from Rock Auto and will switch it out next week before springing for a more expensive repair.

 

^^RJ's suggestion wil allow you to refine the guess.

If it is warped you can then seek a replacement. If the downtime isn't an option then put it all back together using the old gaskets for the time being as you're not going to be much if any worse off?

 

I installed a new left side gasket and the leak is improved, but still there. I don't have any spots on the floor, but still have the hot oil smell. I am tempted to try the RTV suggestion for the whole surface.

 

If you don't actually see oil leaking, but only smell it, it could be residue that hasn't burned off yet. Give it some time for the smell to go away?

Was the valve cover warped? And you did put dabs of RTV on the designated spots, right?

 

Success! The oil smell stayed around for a few weeks and became stronger before disappearing completely. I think it was burning off old deposits because there were no leaks. So, I think I am done dealing with a leaking valve covers for the time being.