philbert

I take public transit to work, and we use my wife's car to run many errands, so my S2000 doesn't see a lot of miles per year (2-3k), though I do attend a number of autocross events.

I followed the 1yr rule for my first oil change, and it's coming up on that time for the second, despite the maintenance minder showing 70% oil life. I should disregard that reading and change at 1yr due to potential moisture in the oil?

Given that I change based on time, vs by mileage, is any potential benefit of synthetic oil wasted in my case?

Also, given that I autocross, what is a recommended change interval for the differential and transmission fluids?

Thanks,
Phil

INDYMAC

If, when you do get to drive the car, you drive it long and hard enough to heat up the oil (30-60 minutes), then stay with the 1 year OCI.

If you are using it to run short distance errands without many 1 hour romps, then change it every 6 months.

If you really want to know what condition the oil is in after an OCI, then do an oil analysis. That will make you more educated about your choice.

philbert

I did order an oil analysis kit from Blackstone to collect a sample from this upcoming change. I didn't know about them or UOA at the time of my first change.

What about the differential and transmission fluids?

jeffbrig

My car has averaged ~4k miles a year. I've changed the oil as short as 6 months to as long as 11 months. I've always used mobil1 synthetic. I usually change the transmission fluid at the same time.

INDYMAC

I change the diff oil whenever I think the tranny fluid needs changed. This is a subjective thing with no mileage associated with it. The tranny will start to feel like it just doesn't shift as well as it used to. Time to change the tranny fluid.

The diff only holds about 0.82 quarts of GL5, so I don't think there is such a thing as changing it too often.