Has zinc been removed from motor oils?
“I am having thrust bearing failure in a 4.6 modified performance engine. This is a street/strip engine. Many of my friends are having the same problem. I think it is the result of the removal of zinc from the oil. I was told by two separate racing engine builders that the EPA ordered the removal of the zinc from over-the-counter motor oil. I use Mobil 1™ 5W-20. Is this true and do you think a zinc additive might help?”
Randy Lovejoy, Americas, Georgia