XJ XJ8 / XJR ( X308 ) 1997 - 2003

valve cover gaskets leaking so soon?

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  #21  
Old 04-21-2015, 11:30 PM
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I have the blue Felpro gaskets on the car still. The passenger side sealed fine, but I was struggling with the drivers side (LH). I generally under torque in such applications, at least slightly. So, I tried tightening the three bolts around the leaking corner. The leak diminished to almost nothing but did not go away. Eventually, it got a little worse again. So...I loosened all three of the adjacent bolts and re-torqued them. This time with even less torque than the first time. The leak appears to be gone completely now but it's too soon to call it a victory.

I already ordered (and received delivery) of a black replacement gasket (Qualiseal?) for the LH side. If the leak re-appears again, I will remove and thoroughly clean everything and then install the new gasket. I am hopeful though that the re-torquing has worked.
 
  #22  
Old 04-22-2015, 11:27 PM
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Default Sixth time in 3 weeks

The valve cover was still smoking a little, so I went ahead and removed it again (sixth time). I thoroughly cleaned the cover and mating surface on the engine; got every last bit of the black rtv off. I installed the new qualiseal (black) gasket and torqued the 14 bolts in the perfect sequence, very slowly. I probably turned each one five times in sequence before they were all snug on the last pass. I then torqued to the lower part of the recommended range, about 9nm. I even put a light coating of motor oil on the mating surface as someone recommended to help the gasket seat properly.

Still smoke coming out of the bottom rear corner; even more now. I torqued them all a little more, smoke was a little less. Torqued them all a little more again, a little less smoke. I finally got as tight as I'm willing to torque them (which is not terribly tight but certainly on the upper end of the torque range) and still a small amount of smoke out of that bottom rear corner.

The cover looks perfect. I looked for cracks with a magnifying glass, found nothing. I am at a loss. I've owned the car three weeks now. I've successfully changed the secondary tensioners, water pump, thermostat and housing (went with aluminum), part load breather hose, serpentine belt, throttle body gasket (removed it for cleaning) and various other smaller maintenance items including the valve cover gasket on the other side. All that and then to be beat by a simple valve cover gasket?
 
  #23  
Old 04-23-2015, 07:19 AM
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Originally Posted by luc
....And this comment would be based on which facts?
Since the Lincoln LS use the same engine, beside Ford, a couple of after-market brands offer this gasket, one of which ( FelPro) has a stellar reputation.
My valve cover gaskets were replaced (my rule of thumb: if you separate two assemblies with a gasket in between them...they get replaced with new when you reassemble...blame it on A&P tech schooling...) when I first bought the car and had the top end inspected for the tensioners (the engine is a late run engine with the dual row primary chain and all metal tensioners...we found out); the wrench used an aftermarket kit...which started weeping within a couple weeks of having them installed. This was the felpro kit (the wrench is a 25+ year Jag-trained wrench, so, I do trust him to Do the Right Thing). Just my experience, and may not be a general experience.

Had the gaskets and seals on the valve covers replaced with OEM parts. That was January. No weeps, leaks, smoke, smells (that aren't supposed to be there) since then, and the oil seems to be staying on the inside.

IMHO, considering the small delta in cost, using the OEM (whether from the Jag or Ford parts counter) for me was worth it to not have the smell of hot oil hit me in the face (and impress any passengers) when I open the door.

That's my experience. Others may rightfully differ, and that's ok. But, having put 8K on the clock since January (12 K since I bought the car in September), it's turning out to be a decent car for my purposes...)
 

Last edited by bdboyle; 04-23-2015 at 07:22 AM.
  #24  
Old 04-23-2015, 10:11 AM
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Default RTV question

Thanks,

I will consider ordering the OEM gasket. In the short run, I elected to remove the cover again this morning (seventh time - I can have it completely off in like 10 minutes now!) and try something else before I replace a brand new gasket.

I put a coating of black RTV along the leading edge of the gasket. I read in a post where Vaseline or silicone is recommended, and so the RTV is silicone, technically. I torqued the cover down again, in sequence, to just a little past hand tight.

How long should I allow the RTV to dry before starting the car? I fear that the last time I tried RTV on the old gasket I waited less than two hours and maybe the gasket was not strong enough yet, thus started leaking.

Thanks so much
 
  #25  
Old 04-25-2015, 01:12 AM
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harvest - the valve covers can warp; I recently had a recurring valve cover gasket leak, and had both aftermarket and oem gaskets put in, and the leak kept coming back both times. I bought a new valve cover, and now there are no leaks.

From a number of online retailers you can get new covers for 250-400 (depends on the year, model, and which side), and they come with all new jaguar gaskets and rubber bits (which are over $100+ on their own anyway).

When I did the gasket job, I left the sealant on overnight like 16hrs w/o starting the car. The package recommended a day.
 
  #26  
Old 04-25-2015, 03:04 AM
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Hairline cracks in the plastic covers are a known issue as a result of over tightening.

Graham
 
  #27  
Old 04-25-2015, 08:11 AM
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Default warped makes sense...

I let it dry for a little over 12 hours. There was only the tiniest bit of smoke coming from the lower bolt next to the corner bolt after that. I put RTV around the head of that bolt and now do not see any smoke.

One of the times I removed the cover it was still quite hot. I wonder if as it cooled without the benefit of being pressed against the engine it deformed slightly?

For now all is OK, but I will be keeping my eye out for a new replacement valve cover at a good deal.

Anyone have one for sale?
 
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