Just a reminder that most cars are operated under the adverse conditions maintenance schedule. In this example, the first service interval is 3000 miles, not 7500 miles. Even the highway-driving-only service interval suggests biannual oil changes.

Short trips don’t warm the engine enough for the oil to fully do its job, in particular, water never fully evaporates out of the engine’s oil, which leads to further contamination and is why shorter service intervals exist at all.

This is for a light-duty truck that I’ve been wrenching on. My van’s maintenance schedule is even more aggressive, recommending oil changes every 90 days. It’s easy to service and doesn’t require jacking it up, so I mostly follow the schedule.

That said, the van’s overbuilt. If I left oil in for a year, it wouldn’t be catastrophic—it would still run—but I’d likely notice changes in sound and throttle response.

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