I've been having issues of oil coming through the spark plug seals on the valve cover, causing a misfire. I just got a 'new' used valve cover that I'm told 'doesn't leak', and new seals/gaskets for everything which should finally fix my problem. I already replaced the spark plug seals twice to have them harden and fail, so the new cover should fix everything.

The question is... should I use a sealant, or gasket maker in addition to the new rubber seals? I didn't before because I was under the impression not to.

 

I used Permatex Ultra Black on the half moon seals at the rear of the head, but that's all. No leaks after a year.

 

+1


Cheers
DD

 

I put black gasket sealer around the spark plug well seals. I've had several cars w/COP's and though it's been disputed I'm still convinced oil seepage into the wells is no good for the coils as capillary action will draw it up the boot and the coil has to work harder to fire through it. One of my wells is distorted at the bottom so sealant is a must there. IMHO it isn't going to hurt smearing a little on each side of the well seals and also the half moons.

 

+1
The casting quality in the plug wells certainly is questionable. If I had leaks in the well seals I would do the same.

 

I found it difficult to ensure that the gaskets all stayed in place when resetting the cover.

I found this:


It is awesome. It is exactly what you need. Using a gasket maker, or RTV can make it very difficult to replace the gasket in the future.

 

I found the best way to hold the plug well seals and the main gasket in place for correct alignment was to mount them on the cover with a dab of permatex ultra black, just enough so they don't fall off as you lower the cover onto the head. I also used permatex on the head to seat the half-moon rear seals.