When does car oil go 'bad'?

Conrad3000

Hi all.

I only do about 3000 miles a year and find changing the oil annually a bit of a waste.

So does it depend on the mileage or how long the oil's been in the car?

An extreme example: If someone's just changed the oil and they've only driven about 3000 miles in the last 3 years, would they still need to get rid of the old and put in the new?

Does it have a long or short shelf-life?

Thanks.

bengalknights

You generally change the oil to get rid of any dirts that may have entered and could cause damage to engine, it also helps maintain the efficiency of the engine.

AdrianC

One of the things that causes oil to degrade more rapidly is doing short journeys. The oil never gets hot, so contaminants don't get burnt off.

Stubod

Ideal world you should change the oil annually (or around 12k miles whichever comes first), regardless of low mileage. However some people would probably suggest that for low mileage you may get away with every other year.

We had an older low mileage car (3k per year), that we put away for the Winter and only changed the oil every 2 years. (Would not leave it any longer).

In reality an oil, (and filter) change is not that expensive in the grand scheme of things particularly if you can DIY, and if the car was newer I would still do it annually.

(I have a lawn mower which i don't think has ever had an oil change in the 10 years I have had it, probably about due then!).

Nobbie1967

If the 3000 miles over 3 years was done in 10 journeys then it probably wouldn’t need changing, but most cars that do low mileage like mine, do it in small trips. Mine rarely goes more than 10 miles and most trips are around a mile. I do 3000 a year and change every year as the oil get’s mucky due to seldom getting upto full temperature and running rich during warmup. Luckily it’s a 107, so doesn’t take long to warm up.

born_again

Conrad3000 said:

Hi all.

I only do about 3000 miles a year and find changing the oil annually a bit of a waste.

So does it depend on the mileage or how long the oil's been in the car?

An extreme example: If someone's just changed the oil and they've only driven about 3000 miles in the last 3 years, would they still need to get rid of the old and put in the new?

Does it have a long or short shelf-life?

Thanks.

Regardless of mileage the car still needs servicing each year. Low mileage, while should be less wear. It means things rust faster. Tyres crack due to lack of use. Oil does not burn off moisture due to not getting hot enough. 

Low mileage cars can have more issues than a high mileage car. Simply through lack of use.