Exactly what I was worried about. But to answer Healingbear when I used it in my buddies Lexus, I had just done an oil change (figured it would work better with clean oil rather than old dirty stuff) and put a new filter in. The only major thing I noticed with leaving the seafoam in the crankcase is it smoked a lot more (the Lexus already burns oil but the seafoam sure adds to the smoke). The bottle nor website say if you should add to new or old oil, I've only done to new and have had no problems. My 4runner is running quite amazing now actually. Personally I see no harm being done in new vehicles but I'm worried about, as Roy said, messing my bearings.


Josh

Josh's money pit!