Originally Posted by SubieRubyRoo
Originally Posted by Pablo
Amsoil leaves a slight yellowish brown "stain" - on Al surfaces after years of use. I believe as Terry said, it's mostly EP adds. In my experience AutoRx will NOT even touch this coating. (Even after 3+ treatments and the car running better than new)
It is definitely NOT something to worry about. It does bother me when people categorize this coating with real "varnish", which is quickly (mentally) associated with sludge.
This is what I was talking about. People generally associate the brownish tinge under the valvecover area as "varnish" when it is not actually so. So that was my point to the OP, until you really know if it's "varnish" or "EP fallout" it doesn't really make sense to try to attack it... and since he's been using syn oils for a long time, it's probably more EP fallout.
This is varnish, and could become a concern:
This is EP fallout, and probably more likely what OP is considering varnish:
Well, I must say I learnt something today. I had no idea. Thanks for teaching me!