Years ago a bought several cases of Castrol oil. Today, I'm down to putting the last 4 quarts in the 914. The containers have never been opened. Still good? I'd think it would still be alright to use.

An excellent question & I have no answer. But....

I did the same thing about a dozen years ago, with Castrol GT. Changed oil every year whether it needed it or not (rarely needed it). Then I started thinking (yes, dangerous).

If my oil degrades in a virtually unused crankcase, why wouldn't it degrade on the shelf? Does contact with metal make the oil less worthy? Don't know, but I recycled my unused Castrol last weekend.
P

I wouldn't think it would degrade in a sealed plastic container. In an engine with exposure to; air, moisture, different metals and gasoline, that's another story.

I can answer this with some tribal knowledge. It can separate. Especially paraffin based oils, think Castrol is ash based. Anyways, we see separation in our oil analyzer at work, and in the machine supply tanks. Part of the PM's is to change the oil and clean the tanks, and you can really see the muck in the bottom of the tanks from the oils that does not circulate. Don't know if I would trust it to re-mix in my engine.

Years ago I bought a car the had a case of Texaco Havoline oil sitting in the back. I used it for an oil change in my Datsun truck. I did not know how old the oil was but figure it would be fine. It seemed fine when I put it in and everything was fine for a couple day. But then it would not start, acted like the battery was dead, cranked slowly. I jumped it and that did not help either. Eventually I traced it to the oil which had turned into a gel. No apparent engine damage and changing and flushing the oil out got me back on the road.
I won't embarrass myself with how long it took and what I tried before I looked at the oil.


Jim

I thought the reason you were supposed to change oil once a year if the car had been sitting was due to water in the oil due to humidity and condensation. Since the car is not running, the water never burns off and can build up. Especially if the car is run every now and again but never long enough for the oil to reach operational temps.

Zach

The industry standard is 3 years, especially if the storage area is exposed to humidity.
Separation is the main issue... If that Castrol is newer than 2002 it's not worth the hassles associated with it, that's when Castrol changed... It was one of the first.