I just use it to commute. Manual says 7,500. Is there a time limit on the oil? I assume oil doesn't expire, so if I reach 7,500 miles every 1.5 years, is that still an OK oil change interval? 7,500 miles/1.5 years?
Oil does degrade with time in the crankcase; water and oxygen can get to it. The plug in Prii have a max of 12 months for the oil change interval. The Volt can go two years between changes. We put low low miles on our Sable, and I did an oil change once a year with cheap oil. Using a synthetic, going longer shouldn't be an issue.
