I use a 3 ounce maintenance dose of Auto-Rx with Amsoil to, I would check with Frank or get a used oil analysis ( UOA), check with Blackstone Labs, they do oil analysis, you can also find more information about the maintenance dose on BITOG, also how many miles do you have on your engine, if it is above 25K you might want to do a clean and rinse, hope this helps!
