Leaky Valve Covers

[75sierraclassic]

I did a quick search and didn't find any info on this, sorry if its already been covered. What do you guys do to get your old style valve covers (side bolts) to not leak. I've tried just massive amounts of RTV (didn't work), I bought new more rigid aluminum valve covers and a high dollar Fel-Pro rubber gasket (also didn't work). It seems like it will seal up for while then start leaking again. I'm tired of having an engine compartment that looks like crap, there's oil all over the place from years of slow leaks. I know there is some way to do it, I just haven't found it yet.

[cliffsta]

When you figure it out, I wanna sell you a bridge...

We've done everything short of putting different valve covers on my truck, which will probably be the next step. Only thing I can suggest is to do it like say an intake. Shave and hack and smooth the surface on the heads until you could see yourself in it, do the same with the valve covers, match them up and see how well they fit or if they need to be bent, then gasket and RTV.

Or accept the fact its gonna leak. I have

[mhicks]

Clean the head and the valve cover with accetone using a clean rag for each quarter of the way around the head and valve cover and then use RTV.

[MylilBowTie]

Have you tried cleaning the cylinder head mating surface really good? I would wipe it down with some brake cleaner on a towel or rag to get it ready. Have any pictures of where its leaking? Are you sure its the valve covers leaking? How do the oil returns look?

[84 400]

pre soak the gasket in marvel mystry oil and make sure the surface is clean

[75sierraclassic]

Originally Posted by MylilBowTie

Have you tried cleaning the cylinder head mating surface really good? I would wipe it down with some brake cleaner on a towel or rag to get it ready. Have any pictures of where its leaking? Are you sure its the valve covers leaking? How do the oil returns look?

I've wiped down the heads with carb cleaner until you could eat dinner off them. I know that my intake is leaking too, but there is oil crusted on my header flanges and it is obviously leaking form the valve cover. Its also leaking down the front of the heads and gets blown around by the fan or belts so that everthing kinda has a nice mist of oil on it.I guess I just need to take them off and clean and reseal every 6 months.
You mentioned the oil returns, I assume this is where the oil drains back down through the heads? I have wondered about my oil pump. When I rebuilt the motor I used a high volume oil pump to where when under throttle the oil pressure pegs out the stock gauge of 60 psi. I wouldn't think that there would be this much pressure under the valve covers though, right?

[bigblock73]

Be sure the VC mounting surface is straight on the VC! You can also get spreader bars that will more evenly distribute the torque of the bolts to more of the flange...and not just where the bolts tighten to. Like others have said, be sure the cylinder heads are clean and free of debris prior to VC install.

[beaterC10]

I had the same problem until I tossed the chrome covers in the trash and found a set of stock covers and spreaders. I cleaned everything up, glued the cork Felpro gaskets to the covers with the purple shellace gasket sealer and snugged them down. No leaks since April of this year on my daily driver.
I have come to the opinion that most of the chrome dress up stuff is junk, it will rust and won't seal.

[MylilBowTie]

I agree that most of the chrome especially the cheap kind don't seal well. This is because of cheap materiel and chrome along with being very thin. It doesn't take much to over tighten them then they get warped. This is even pretty common on stock stuff to if you get carried away. If you find that they are warped, look strait down them with them flipped over. Look for overall straitness and be sure to check around where the bolt holes are. Sometimes you can get luck and use a small tapping hammer to get them back in original form.

But if you have tried tons of silicone and aluminum valve covers I dunno why that would still leak. I don't like using silicone on valve covers other than from the gasket to the valve cover to hold it in place. I don't want the excess silicone floating around in the engine waiting to clog something up.

Aluminum valve covers are the way to go to avoid warping them from over tightening. But they cost a lot and if you are careful good steel ones will get the job done.

I would use some felpro gaskets and there are two different thicknesses. I would try the thicker of the two I forget the size. This helps to seal when the thinner ones don't.

Do you have studs in your cylinder heads for the valve covers? If the oil returns are sludge up oil has a rough time to get back to the oil pan. The HV oil pump shouldn't hurt anything at all.

[Nolowrider]

I personally don't like the rubber gaskets. I suggest using the cork, been there done that. Also, don't tighten the screws too much, they don't need alot. Just snug. Use the spreader things from any auto parts store. Are you absolutley sure it is the valve covers? I chased what I thought was a valve cover leaks for weeks to find out it was the pipe plug under the fuel pump rod. The rubber gaskets belong in the trash.

Do you have a oil breather in the cover. What about the PCV? The high volume pump should not be a problem. If you installed a high pressure, that could be a problem. Are you sure the leaky intake is not drifting over to the valve covers. Oil will travel, especially on a hot block.