quote:
Originally posted by Brat57:
if you do a lot of short stop and go city drivng and then do a hiway trip of 50 miles or more at hiway speeds does that "burn off" or heat up and evaporate the fuel contamination in the oil. i assume that the fuel is not fully cooked off though, am i right?
also if you were on an exptended drain interval with syn and a big oil capacity (8qt) and wanted to "freshen the oil" by either changing the filter OR replacing the oil, which would be better?
i am planning a UOA at 5k on my '04 MB CLK first but want to plan ahead in case the fuel contamination is on the high side.
I may be out to lunch on this, but my understanding is that gross fuel dilution, of the sort that made that a major issue, is really only an issue on older carbureted engines, which compared to today's cars, did a miserable job controlling fuel. Choked up (literally) for starting, they ran horribly rich. Then, the designers would have to set the carb to provide enough richness for even the leanest of the cylinders (usually the one most distant from the carb). The flipside, of course, was that all the other cylinders were running with too much gas.
Nowadays, we have multiport fuel injection, adjudted to optimum mixture a zillion times a second by a computer that's literally a few thousand times more powerful than the first computers installed on the Space Shuttle.
My thought is that if you have a 2004 Meredes that's dumping bulk fuel into your oil, something is awfully, awfully wrong and you'd better be at your dealership demanding a bit more than an oil change.
Oh, here's a simple answer to you question: Yes, a good long highway run should, in an otherwise properly running engine, burn off (perhaps boil off would be a better term) any volatile contaminants in your oil, including fuel.