Yes, I know the sea foam. My last car was a 78 Ford Fairmont wagon and I got
used to using it every oil change. It had a gasket that would leak coolant
into the oil when it was running hot (NYC traffic), and this stuff seemed to
actually clear that dreaded milky-ness out of the oil until I could do a
change. Honestly, don't know what happens at a chemical level, but I don't
know how dry gas works either.
    I still use it every six months in the Vanagon fuel, or when I know I'm
going to run through a tank quickly on a long trip. Yes, it does feel
different, and better.
    In addition to being an oil additive and a carb/injector cleaner, they
recommend this treatment every 5000 miles: w/ the engine running, pour
directly into the carb or air intake until it stalls. Wait 10 minutes. Start
the engine. Incredible amounts of smoke is produced in the exhaust, but you
can drive it off pretty quickly. Really big improvement in performance, for
a while anyway- I guess until the underlying problems that got cleaned out
regain control. I've never done this to a vanagon, though.
    Sea Foam was recommended to me by my cranky local NAPA guy. It does seem
to work on carbon deposits, which for daily urban driving is really serious-
low RPMs, plus either hi-temps in summer or never really warming up in
winter. Right now, though, it makes more sense to change my driving habits
than to be using additives all the time that I don't really understand.
    I have used MMO sometimes as well, and in appearance it seems to be very
similar stuff.
    If it is of any worth, I lost that amazing ford to rust, not engine
trouble. I still miss it. I don't really follow car evolution much, but it
seemed to me one of the last simple, utilitarian, US cars.
-Matt Sutton
88 GL