Welder Dave
Senior Member
Had a Hino that needed the throttle set about 1200 RPM or it could idle all day and not warm up.
If it didnt come out new with synthetic you are asking for trouble using synthetic. I hate the stuff but if ever bought something new that used it i would stay with it.I wish i had a Dollar for every time i had to talk some one out of using synthetic in a old high mileage engine.Just as a comment regarding synthetic oils, i used to have an old turbo 6.5 GM rattler vintage '98. Ya go ahead and laugh now. Summer i used shell rotella 15w-40 and oil consumption was minimal. Winter i used shell rotella 0w-40 for better cranking and starting, plus its easier on the oil pump(they have weak oil pump drive ). The 0w-40 is a full synthetic and using it the oil consumption would triple or quadruple and the front and rear main seals would leak. Then summer again, back to 15w-40 and it was back to normal oil consumption and no leaks.
I think it's more about the whole combustion process that degrades the oil and additives . We used to maintain a fleet of converted gas-jobs running CNG. The drained oil looked as good as what we were putting in. No soot or burnt hydrocarbons to get suspended. We never sampled those so i have no idea if the additive package was compromised.My Father was Bomber mechanic four years in WWII, then another two years Korean Conflict. These planes weren't expected to last a year, but oils were stored & shipped back to a refinery to be renewed.
I'm sure the molecule that makes up oil doesn't much change except oil burning on the cylinder walls, then transferring to below the piston by reciprocating or blow by. It sure does get contaminated! In my observations, diesels much worse than gasoline engines.
We deal with generators, near all of them run on propane. We do service on them at least annually. Oil is not black, but always cloudy, (water). A few machines will be in special locations where oil gets quite milky. One, on a lake, we change oil twice a year to control how much water it contains.I think it's more about the whole combustion process that degrades the oil and additives . We used to maintain a fleet of converted gas-jobs running CNG. The drained oil looked as good as what we were putting in. No soot or burnt hydrocarbons to get suspended. We never sampled those so i have no idea if the additive package was compromised.