I've noticed some oil accumulation at the head gasket lower bolt locations on both heads (adjacent to the spark plugs). Its got 35k miles and I haven't cleaned the engine for some time so its leaking slowly.

Do you think I should just try tightening the lower bolts or not touch it? Being aluminum I'm thinking it might be better left alone or do those bolts need to be re-torqued over time?

Thanks in advance for any help.