This may sound like an uneducated question, but is there any evidence that PAO based oils (such as M1 EP 0W-20 that supposedly has 60-70% PAO) will cause oil leaks because they do not swell seals as good as something like a Group III(or III+) synthetic or ester based oil? Such as will it over time if I ran an engine on M1 EP 0W20 would have likely more oil seepage than something like Castrol EDGE 0W20 black bottle (mineral oil based/largely group III)?
I am asking because I read somewhere else (can't find the webpage anymore) that it mentioned that PAOs shrink/harden seals.
I am asking because I read somewhere else (can't find the webpage anymore) that it mentioned that PAOs shrink/harden seals.