Originally Posted by Sol
Isn't it true that if you have an old engine, switching to synthetic is a bad idea because it might be leak prone?
What i've heard (makes sense) is that regular oil can gunk up holes so you don't get leaks. The extra detergents in Syn cleans out your oil (why it gets dark quicker on your first couple changes) and doesn't leave deposits. It also flows a lil better, especially when cold.
Whether or not a car will be safe depends on how clean it is in the oil passages. I switched @ 112, and i'm good. My oil pan gasket might drip every now and then though.