Now to rile up the arm chair quarterbacks, the facts by Shell oil engineers state that the oil gets acids in it when it sits after being ran. This occurs when the by produces of combustion and the moisture mixes within the crank case is converted to acids and they will start to eat away at different parts of the engine. 6 months on an oil change helps prevent this on an engine that is occasionally driven. The only way to prevent this is to get the oil temps up to 140* F for an hour to evaporate the moisture each time you run the engine.

Also oil does have a problem after it sits, when the manufacturers put the additives in, they do it at specified temperatures, typically they can begin to fall out of suspension within the oil after 4 years. It may not always happen in 4 years but manufactures have tested and proven it WONT in the first 4 years. Only testing can demonstrate whether they have or not. For the cost of a case of oil, I will use only fresh. Tim