Q: I have a Lycoming O-360-A1A that had a prop strike and was rebuilt at Western Skyways. I was told by my test pilot to change the oil after five hours of flight.
Is this correct? If not, at what hourly interval should I change the oil to safely monitor the break-in?
A: Chuck, your question is one that is easily answered and I hope many of our readers will follow the information provided.
The best source for your question can be found in the latest revision of Lycoming Service Bulletin 480.
I certainly can’t argue with the suggestion that you change the oil after five hours of flight, as long as you also inspect the oil filter element or oil pressure screen in addition to inspecting the oil suction screen in the oil sump.
Even though Lycoming suggests the first oil drain be at the first 25 hours, I prefer the five hour drain and filter and/or pressure screen inspection.
I feel that oil is one of the least expensive things you can put in your engine and this first five hour inspection will give you peace of mind knowing what’s going on in your engine.
Your future oil change frequency depends on whether you have a full flow oil filter or just a pressure screen. If you have a filter, the interval for changing oil and the filter is 50 operating hours or no longer than four calendar months. With a pressure screen, the interval is reduced to 25 operating hours, but still at four months.
The primary reasoning behind the calendar time requirement is to remove the engine oil that is contaminated with condensation and the by-products of combustion that contribute to internal engine corrosion.
Also, don’t forget to inspect the oil suction screen located in the oil sump.