VCCA Home Forums GENERAL DISCUSSION New User Forum Valve cover gasket

Hello...I'm replacing my valve cover gasket with a cork gasket from the Filling Station. My question is, should I use a sealant on one side of the gasket, both sides, or none at all? What sealant should I use if recommended? Thank you in advance.

I expect that you will get many different opinions about how to do what seems to be a simple task. The reality is that unless you pay attention to the details you will have leaks.

The first step is to make sure that the sealing flange all around the valve cover is completely flat and perpendicular to the sides. Over time people will keep tightening the nuts to try and stop the leaks. Eventually this bends the flanges as well as collapses the area where the nuts sit. I assume you are dealing with that style valve cover, not one with bolts along the sides.

My preference is to use a light coat of silicone gasket sealer as an adhesive to make the gasket stick to the valve cover. I use that approach because the selling surfaces on the head are larger than those on the cover except at the rear. After I know that the gasket is sticking to the valve cover I very carefully drop it as flat as possible on to the head while watching the positioning very closely. If you need to slide things around lift the valve cover slightly. You do not want the gasket to slide out of position.

It is critically to carefully check the back end of the cover. I use a small inspection mirror to make sure I can see the gasket between the valve cover and the head. The gasket can slip forward back there if you are not careful.

Makes sure that the rubber grommet seals under the nuts are in good condition. You do not necessarily need to replace them every time you replace the gasket. They do get hard and crack with heat, age, and oil.

Install the nuts snugly but do not over-tighten them. You want enough tension to hold the valve cover firmly against the head. If you started seeing the valve cover flanges bend or the steel under the nuts dishing down, stop tightening.

Thank you Rusty, as always, excellent information.

Instead of silicone, grease works and is easier to remove if/when needed.

I am not a fan of RTV type silicone gasket sealers. They lack adhesion that some of the alternates like Permatex No. 2 or No. 3 have. The non hardening sealers have advantages if you need to take the assembly apart in the future. They also allow some adjustment when the parts are being put together.

I agree with Chipper that whatever sealer you use needs to have adhesive properties. It also needs to allow some movement to make sure everything lines up well.

My experience is that the most important part of the process is to make sure that the sealing surfaces of the valve cover are flat and square so they sit uniformly on the gasket when the gasket is on the head. I test fit mine before attaching it to the valve cover. Otherwise it is irrelevant which sealer you do or do not use.

I also agree with Chipper.
And with Rusty as well.

I haven't had great luck with silicone either, and much prefer products like Permatex Aviation which is non hardening.

In the past I've been a "coat both sides" guy, but I actually put the last rocker arm cover gasket on my truck dry.
I did so because I knew I'd have the cover off again shortly anyway.

That said, I think a better way to go is to use gasket sealant only on the "bottom" side of the gasket, between it and the head.
The reasons I will be doing it that way next time I check my clearances are:

1 Oil pooling on the top of the head may be more likely to leak past the bottom edge of the gasket than the top edge.
2 When I remove the cover next time, I would prefer the gasket to remain with the head. That way it won't get caught on something and get torn off the cover on the way out.
3 When I replace the cover it will settle down into the groove the cover left in the gasket from before. That plus the gasket staying put because of the sealer holding the gasket in place will assure easy alignment.

As always though, to each their own. There are no "right" ways to do something like this. :-)

Thank you Stovblt, that was very helpful!

As Rusty mentioned, make sure the flanges are straightened and not like the valve cover in the first photo. After gently tapping the flanges against a straight piece of metal, my valve cover seals well. I used a light coating of wheel bearing grease on both sides of my gasket.

Use Gascacinch to cement the gasket to the head . It can be easily be removed for replacement. Been doing it for years. You're welcome. Hendo

Thanks Hawkeye and Hendo...more to consider.