Originally Posted By: fdcg27
When was it not okay?
This.
I have never bought into the automotive "old wive's tales" that get repeated tens of thousands, even millions of times in the back of shade tree shops by those who consider themselves experts on teh subject because they heard it from their brother-in-law's childhood friend, who works at a Ford dealership, who heard it from one of the old timer mechanics, who heard it from a Pennzoil rep.
Show me the science. Give me evidence. Without it, all you are doing is decreasing your credibility when you repeat these stories to me. I still live by the motto that used to hang over our office at one of my jobs. In God we trust. All others, bring data.