I had a VL commodore that I ran on Mobil 1 for 6 years it did a head gasket and when I pulled the head of to replace it the motor insides were very clean for a car that had over 160,000 Kms on it. I'm now using it on a 2000 model Camry with the 1MZ-FE motor with 109.00KMS and intend to keep using it as I've read reports that this motor has a tendency to sludge up so using a good synthetic oil with regular oil & filter changes should prolong any problems of this occurring and have to agree one of the best oils ever made.