CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Okay to use 3M Weatherstrip seal for Valve Cover Half Moon Seals?

I have some half moon seals where the valve cover attaches into the engine. I’ve seen in some videos that you’re supposed to take them off and reapply some silicon to it. Would 3M weatherstripping suffice? (https://www.amazon.com/3M-08008-Black-Weatherstrip-Adhesive/dp/B00063X38M/ref=sr_1_2?crid=JK9F4YJ1DTLV&keywords=3m+weatherstrip+adhesive+black&qid=1549612190&sprefix=3m+weather%2Caps%2C171&sr=8-2) Would rather not have to buy a new product.

Use gasket sealant instead…its very inexpensive.

1 Like

3M weather strip adhesive has been around for decades and is widely respected and used by professionals and is obviously a great product, but…

… it’s for weather strips! Unlike weather strips, engine gaskets are subjected to oil and high temperatures. I’m not sure what would happen to the 3M adhesive if used, but why not use the right product?

Hey, you’re already saving the lion’s share of the replacement cost by DIY, eh? I’m extremely thrifty, myself, but one can be penny-wise and pound-foolish.
CSA
:palm_tree::sunglasses::palm_tree:

1 Like

Second vote for not using weatherstripping for engine gaskets - same reasons!

1 Like

“Fel-Pro PermaDry valve cover gaskets made of premium molded rubber are designed for engines that were originally equipped with molded-rubber gaskets.”
most molded rubber gaskets i see are black. these are blue. i have seen some referred too as silicone while most say rubber?
i got some rubber ones and they leaked after 3yrs. i took them out and they were so hard they snapped as i tried to bend them. not pliable at all.
so, maybe the brand of gaskets you use might be more important than sealer?

No. Hot oil isn’t what it was designed to seal. On the positive side, it might not burst into flames.

Spend a couple bucks on automotive gasket sealer. If you use really want to use the stuff you have, do a web search for the product’s Safety Data Sheet (SDS). That may tell you whether it is a silicone or not. That the seller mentions it is resistant to temperature extremes and given that it is rubber-like, leads me to suspect that it is silicone.

@cavelle, rubber is a generic term, and there are lots of types. Silicone rubber is one of them.

and to think i used to design pumps and had to spec out seals? i did a lot of guessing.