Originally Posted by laneygirlid
I am actually in the midst of trying to make a decision on whether to switch to synthetic or not. My previous car was an 1997 Audi A4 1.8T Q and was told to use synthetic because Audi/VW won't warranty turbos that didn't have synthetic oil in the engine.
Now, Subaru is not saying anything about synthetic for turbo, etc. The service manager at local dealer says older mileage cars can convert to synthetic, which is contrary to the leakage theory you mentioned.
I've also been told that once you switch you shouldn't keep going back and forth...I'm so confused. Can anyone provide some objective, more data driven information on this topic?
The controversy is a hold over from the past when synthetic was beginning to make its appearance in the market. The same thing used to be said about when lighter weight oils started to be offered. It was all about gaskets. Gaskets have evolved and now can easily handle lighter weight and/or synthetic oil.
One thing is for sure: syn. oils don't sludge up as quickly as dino and this banjo bolt is yet another argument for syn oil use or at least frequent dino oil changes.