I'm finally getting around to swapping valve covers-I've painted a pair a friend sent to me to clean and bead blast. I'll prep mine and send them to him.

I had the local Chrysler dealership repair the leaking cover on my passenger side a couple of years ago. A soft, red RTV was used and started leaking in ~ 6 months. Re-torquing fixed it until now. I looked into Permatex and Loctite RTV sealants and found that any of either manufacturers "red" colored sealants are not rated for oil. The red RTV they used is actually dissolving in place.

I used Permatex "Ultra Black".

I cleaned the covers (all 4, big and little) first with Simple Green, then carb/choke cleaner, then in the dishwasher. I was, after all, prepping for paint. Removing all traces of the old RTV was the most time-consuming. I found some really great stuff:

DAP #13335 "Silicone-Be-Gone". Works great-melts/dissolves any RTV. Doesn't harm our metals.

A combination of perfect cleaning and the correct sealant, manufacturers' directions followed, as 180 iterated, "to the letter", and proper torquing is the route to follow.