RTV or POLY for valve cover sealant

[84 C2B2]

I'm going to dive in and repair two leaking valve covers. Used Black RTV during a recent rebuild but my right cover is probably bent and left just seeps. I waited until a slight skin and then waited a day until I did a final tighten. Any secrets with RTV or just go with a poly sealant. I figure I've got about 5 more years on this engine before I get the rebuild and power-up urge again.

[jcomp]

I used ultra copper on mine. I cleaned the surfaces, applied a bead, put the cover on, waited an hour then tightened it down. It's been over a year and no leaks.

[odee]

How well does the aftermarket valve cover gaskets work? I have slight leak in the drivers side cover I need to fix.

[john8662]

I've never had any problems with leaking valve covers, and believe me I've had them off a few times.

Just take your valve cover and place it on a flat surface and see if it is warped. If it is, you can probably straighten it or find the high spots. Just take the valve cover off the side of the table/bench and use a hammer to persuade it.

I use Permatex Ultra Black RTV, apply it on both valve covers with them being perfectly clean (take brake parts cleaner to them after you remove the old RTV). I don't let them sit long, just the time it takes me to apply the sealant to both valve covers. I use a 1/4" bead of the RTV on the groove on the valve cover. I don't apply the sealant to the head, just the valve cover prior to assembly.

[Quack_Addict]

FelPro sells valve cover gaskets for the 6.2/6.5L

The 6.5L in my Suburban never seeped or leaked a drop of oil after I installed it - then, one day driving it into work, the left valve cover seal let loose. It lost about 1.5 quarts of oil by the time I got to work. I bought a gallon of Rotella at lunch, filled the level to full, and still had to stop half way home and add the remaining 2.5 quarts in the gallon - and I was still a hair shy of full. The leak turned out to be a TINY pinhole in the sealant bead they put on the valve cover during engine assembly; I'm not sure why it was fine for so long and then just cut loose all of a sudden.

I installed one of the FelPro gaskets with a light coat of the copper silicone on both sides and have had no problems since.