The store manager of my local AutoZone insists if I switch to fully synthetic motor oil in an engine with a lot of miles on it, it may dislodge crud and blow the engine. I know you don't have to have a degree in lubricity to manage an AutoZone. I also figure they attend liability reduction seminars.
His theory sounds like complete hogwash to me.
Tell me he's full of it.
His theory sounds like complete hogwash to me.
Tell me he's full of it.