Originally Posted By: Clevy
Different chemistries will clean different types of deposits than others. I'm really beginning to believe that perhaps rotating oil brands will keep an engine cleaner than just a single brand,due to the competing of the adds.
Just a theory
It's interesting, theoretically each prduct would clean some of what was left behind by the previocus one - or at least it would not contribute the exact same composition of residues & varnish - with the possible trade off of not accumulating protective benefits of continuous use of one formula.
The personal experience with my previous car I drove almost 7 years, frequent switching didn't seem to hurt anything, but in the last 2.5 years I went steady with Castrol Syntec..GC0W30 form May to mid-November, Syntec 5W30/5W20 (3:1 mix)in the winter ... and from that point, the engine just seemed to get better with age & mileage - but that could just be becuse it was an old but low-mileage car when I got it and never accumulated any bad wear or deposits to begin with.