[hurryinhoosier62]

Originally Posted by 78w72

Same here... sometimes 1 or 2 of my cars dont get driven much for whatever reason, working on them or on something else, its hard to put lots of miles on multiple cars sometimes living in the midwest with a shorter driving season than those in year round warm climates.

If i have less than ~1000 miles on the car for the season I dont change the oil, its a complete waste, oil doesnt go bad sitting in the pan (or bottle) in that short of time, same for the filter. If the engine is healthy & not dumping raw fuel into the oil or other major issues like that, the additives neutralize any combustion by products and the anti wear additives dont go bad while sitting. My engines are clean lower mile rebuilds so no high mileage sludge or anything.

I also spoke to valvoline about long term use & was told the same thing, 1-2 years at low miles is not an issue at all, neither is new oil in the bottle for 5 years or more if stored properly. I have & use oils rated SN & SM & even some 15+ year old rotella-T SL grade.... stored in climate controlled area off the ground, shake them every year or so & again before using.

Valvoline FAQ- "DOES MOTOR OIL EXPIRE? IF NOT, HOW LONG DOES MOTOR OIL GENERALLY LAST?
Valvoline motor oils do not have documented expiration dates. When stored under optimal conditions, the product remains stable for an extended period of time. It can be used as long as the American Petroleum Institute (API) rating on the label continues to meet or exceed the requirements listed in your car’s owner's manual. If the rating is still current, we advise you shake the container before use to blend any additives that may have settled."

Combustion byproducts in oil have a nasty tendency to turn acidic in the presence of moisture. I’ve seen it in aircraft recip engines and classic automotive engines as well. Changing the oil is cheap insurance to prevent acid damage of internal engine components.