does oil go BAD sitting

Does engine oil have a shelf life? A friend has had some 50wt in his trailer for along time 4yrs. it has been exposed to cold temps in the winter. (0-10*) when he poured it out it was seperated looked like all the additives sunk to the bottom. 3 of 4 jugs were the same. dumped it all but has me wondering on shelf life regardless of temps. And yes it is a major oil company that sponsors alot in drag racing.

 

I have some 5 year old Penzoil I use. I contacted Penzoil and basically they said the oil won't break down it just seperates, just mix it REALLY well (mixer on a drill) and it will be fine. I did that with my stuff and its perfect.

Corey

 

I have seen some valvoline 70 wt separate like that after three years in a drum--- we mixed it in 5 gal pails with a paint mixer and ran it with good results.

 

Thats sounds better. Im going to send some of it off to be tested. The 70 weight I have looks good.