Shelf life of open oil....

[inkjunkie]

Bike does not take a full 3 quarts....mower does not take a full quart....neither does the tractor so I have all sorts of opened oil containers. Obviously the lids are tightened back down before putting them in the cabinet.....but at what point is this oil no longer useable.....just sorta wondering.....I have always just saved the left over oil for "next time" but is this a good practice?

 

[67Dart273]

I would bet "your lifetime." I have no such troubles. I'm always needing oil 'fer somethin' rusted up, on the lathe, whatever.

 

[ir3333]

what could happen to change it?

 

[67Dart273]

what could happen to change it?

Oil IS organic. "Dead Dinosaurs." There's no reason why given enough time, oil could not deteriorate and or become contaminated. I ain't a chemist, and I don't play one on TV

 

[scatpackbee]

What happens is the additives start separating from the base stock and sink to the bottom of the container.
I always turn the oil container upside down and shake a few times before pouring to insure the additives are suspended.
I attended an oil seminar given by Lake Speed J.R. who is the oil specialist or what I believe they are called "Tribologist" at Joe Gibbs Racing and asked him the same question. He replied the shelf life of oil is a really long time if stored in a controlled temperature.

 

[ir3333]

so...for those that only put 1000 or so miles a year on their muscle car, who have gone more than a couple of years between changes?

 

[fratzog lover]

Moisture and acids are something altogether different. There is no combustion process in a partially used quart bottle...