posted 13 years ago
Change the oil. And filter. For any motor, keeping the oil clean is the cheapest way to long engine life.
IMHO, its silly to skip oil changes, so questions about "required" are not meaningful. When I was racing, we would change the oil every weekend, whether it needed it or not.
As to whether you can, sure, its trivial, most of those Cessnas have simply 4 or 6 cylinder engines, they are just big VW engines. Its obvious where the drain is, where the filter is, etc. Its a trivial job. But I am not an FAA inspector. I don't know the rules. I have no idea if its legal for you to change your own oil, or what verifications are needed.
Airplanes falling out of the sky due to engine failure are frowned upon.