I'm curious what additive you refer to that states it's not to be used more than once during an oil change.....?
But yes.....I've sort of heard this, I think it's more of a marketing thing though, they typically advertise the STP "Complete" Fuel Treatment to be used "at each oil change", or "before" each oil change......
Basically, it's removing the "previous" fuel injector cleaner from the oil, before you add more FIC to the "new" fuel (with the new oil....).
I actually am quite heavy on fuel additives, primarily MMO though....and you can find my Quaker State 5w30 used oil analysis on the used oil analysis forum.....didn't seem to affect my used oil analysis at all.....
I can't recall exactly.....but may have used 1 B-12 CHEMTOOL treatment or some other odd FIC within that OCI too......but yea, didn't seem to hurt anything or set off any red alerts....
But the whole "scare" is that yes, it's possible for fuel to "seep past" the injectors/rings and into the engine oil......so yes....if you are running extremely rich (dumping fuel into the engine and the engine can't burn it all off completely....) - then I could forsee, seepage into the engine oil
But in a properly tuned car....? I can't forsee any ill effects....
I'm guessing it's just a "Cover their [censored]" type of disclaimer
BUT, still curious what additive has this warning
Not to mention...I'd think the high solvency of some of these FIC, would "burn off" after a good spirited, 20-30 minute highway run.....with the engine up to speed....
Another +1 for MMO though
So what if it leaks past the rings, it's safe for engine use anyways
