Back in the old days (twenty years ago), upper cylinder lubricant was a good
idea.
But I've been out of that line of work for two decades, so not as close to
auto trends as I was then. (Do computer networks today.) I do understand it's
a good idea to use an additive to get rid of gas tank condensation, and will
get that info later. Myself, I try to keep my tank full to lessen
condensadation from forming in the first place. (Plus, it's warm here in
southern California.)
I'm unclear on how upper cylinder lubricants work today. I'm reading modern
engines run more "dry" up there than they did in the past. But what do
lubricants in fuel do to smog systems???
-Ray S.