Originally Posted by onehundred80
Yeah, right.
Take a glass jar and fill it with really dirty engine oil and let it sit for a few months. The heavy sludge will sink to the bottom, pour off the clear oil and feel the consistency of the sludge and wonder what that will do as is settles in to the engine oil-ways and components.
The clear looking oil is not too pure either.
Better yet, try this; Ask every mechanic you know, and every mechanic you get a chance to talk to, how many oil related engine failures they have seen in their lifetime. If they have ever seen one, it is most likely to be that there was NO oil in the engine.
Oil related engine failures are extremely rare. The oil companies have done an outstanding job of convincing everyone otherwise.
One of the exceptions here is cars with turbos where you are likely to see a turbo failure in vehicles which have not had their oil changed regularly.
Oil performance while sitting in a glass jar has no relevance to what it does in your engine.
Do you remember the old commercial where they filled two engines with oil, ran them, then drained the oil and ran them until they seized? Both engines ran a lot longer than one might expect, even with no oil.
Still, there is no harm in changing oil too often - just the waste of money involved. Some view it as cheap insurance.