OK, let’s start from the beginning, most of the time if a sheet metal valve cover leaks
, it’s because it’s been overtightned, what happens is the area around the holes distorts a little, the hole gets bent inward, what you do to fix this, and is a good idea to do anyway, is to take a ball peen hammer and with the pan held upside down and the edge of it on a table ledge, place the peen end of the hammer in the hole the stud goes through and hit it with another hammer, hit it pretty hard.
This bends the cover back to straight, or actually a little bend opposite does no harm, just a little though.
If the cover leaks after a new gasket I can almost guarantee it’s distorted, further tightening usually almost always is not the answer it usually makes the leak worse, and if it gets worse with tightening it’s almost guaranteed it’s a distorted pan, distorted pans are very, very common and very easy to fix.
What is happening is the gasket is not tight against the head between the studs.
Hot rodders used to use cast valve covers because they don’t distort, or bend, but if you get stupid they will break.
You only want to tighten the nuts as if they were screws, use a nut driver, that will keep you from overtorqueing, almost always the problem is over tightened, not being too loose.
Goop is never the answer, especially silicone, hydrocarbons, oil
or gas or diesel
will attack the silicone and break it down and you’ll have what looks and feels like slimly bass worms.
Way back in the day people used to use contact cement and glue the gasket to the valve cover, this works fine, but you really need a wire brush in a grinder to clean off the glue, but if you have a wire brush in a grinder you can clean a cover up in short time and the gasket surface looks new.
But never, ever put any kind of sealer between the gasket and the head unless you want a mess and it screams this guy doesn’t know what he’s doing.
You wouldn’t use a granny knot
to attach your sheets
to the jib
would you? Then why would you use goop on a valve cover gasket?
If you ever pull an oil pan, don’t even consider reinstalling it without Peening the holes, it’s cheap
Personally I won’t glue any gasket, paper ones like water
pumps for instance or timing chain covers I’ll use grease to hold it in place, but if you glue one, it can be hell to clean off the next time.
Good valve cover gaskets will last many removals, we used to run roller rocker arms on drag cars and were pulling the covers all the time to adjust valves, there is no pressure so it’s not hard for a valve cover gasket to seal, as long as there is a flat surface.