So a while back i switched to synthetic oil.... some people told me it would cause leaks.. some told me to ignore the other people, so i went for it... today i noticed that i have a leak from the passenger side valve cover.... d'oh.. maybe i'll have to switch back to good ol' napa oil

So a while back i switched to synthetic oil.... some people told me it would cause leaks.. some told me to ignore the other people, so i went for it... today i noticed that i have a leak from the passenger side valve cover.... d'oh.. maybe i'll have to switch back to good ol' napa oil

 

 

Synthetic oil does not "cause" oil leaks. It will however find it's way out through high mileage seals because of it's higher "cleansing" and "slicker" properties of the oil, thus removing some of the fossil oil buildup "crud" from around the seals that was otherwise actually helping to "seal". At least that's been my past experience as a mechanic for an Amsoil dealer.

If it makes you feel any better, I just changed to synthetic on my "new" 91 Legacy ss with 163K and no leaks so far after 2500 mi, except for the passenger side VC near the turbo that was already starting to leak.

Mike