Oil life expectancy - in the crankcase -vs unopened on the shelf?

[Ed_Flecko]

Unless I'm wrong, most oil companies now recommend changing the oil on your car every year, or two, for any vehicle you don't put many miles on. I don't quite understand the reasoning behind that, but it seems to be what is most often recommended.

I also read about some BITOG members who probably hoard more oil than they could likely use in a lifetime. I, personally, only buy oil when I need it and not before then.

I know oil manufacturers are interested in selling their product(s) but they seem to be implying that oil sitting in the crankcase somehow "goes bad". If mostly sedentary oil in a crankcase loses efficiency, somehow, and should be changed based on chronology then what about people who buy oodles of oil to use "someday"? Surely their oil sitting on a shelf is losing its quality, etc., just by collecting dust...isn't it? Do you believe oil in a car that sees very few miles (< 500 per year) should be changed just based on the calendar?

Thank you,

Ed

 

[NormanBuntz]

This was a recent subject. I don't fret about oil age, so long as the oil meets our vehicle specs and it has the appropriate industry ratings.

 

[IndyIan]

5 years for tractor hydraulic fluid is what the petrocanada lube distributor told me. I would assume engine oil would be the same. I had some ~10 year old opened engine oil I found at the back of the shed, with no chunks in the bottom, so I shook it up and used it. My Neon didn't seem to care! lol

 

[Propflux01]

leaving it in the crankcase usually leaves it more acidic (due to normal blowby, etc) than fresh in the bottle where it is sealed tight.. Hence why it is said to change yearly.

 

[ATex7239]

The oil in the engine is contending with carbon deposits, fuel, oxidation and moisture. The oil in the bottle is not. It’s kind of apples to oranges environment wise. Also oil isn’t hygroscopic like brake fluid.

 

[samven]

If you keep your car in a garage and your low mileage is divided into a few long drives that get the oil up to temp and keep it there long enough to burn off any fuel or water you could stretch the time out but if like most low mileage cars they are subject to short drives and many starts or long idling times in traffic then I would stick to the 1 year time table.

 

[marc1]

Do you believe oil in a car that sees very few miles (< 500 per year) should be changed just based on the calendar?

I do not. Once I am out of warranty, I go by mileage and duty. I will, however, short change oil if something extraordinary happens eg. an overheat, dust storm, contamination etc.