I am fighting an oil leak after an opti replacement. A mechanic says that my car needs a new timing chain cover. He says that the optispark o-ring isn't fitting snuggly in the round recessed area on the cover. He says that the round recessed area has changed shape or warped. It is a pretty sturdy aluminum piece so it seems odd that the area can change like. Is this a plausible explanation why the oil is leaking from the optispark?

 

I guess it is not impossible, but seems very unlikely.