Oil Change Question

[Hector]

I'm curious how many ordinary owners with lycoming O-360s and filters actually also check their screens with any frequency at oil changes.  I'm guessing near zero?  I've thought about doing this, but I can barely see the dang thing at the rear of  the oil sump.  And I understand it requires a safety wire, a crush washer, and a torque setting.  I clearly need some instruction from an A&P on doing it, but even then it looks like a total PITA.  I can barely do my filter without making a mess and cutting up my hands, though I'm getting better with practice.  Is it reasonable to do the screen at annual only, unless there's something clearly wrong with the engine or unexpected stuff found in the filter or the oil analysis?

I have an O-360 with a spin on oil filter. I do not check my screen every oil change. I check it during annual only. I do cut open my oil filters to make sure everything looks ok. I replace oil/filter every 30 hours or so because that's when my oil begins to turn a little darker. If I was not cutting open my filters I would be checking that screen more often.

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[ArtVandelay]

>I think that is too long of a calendar time , good oil goes bad.

Oil spent millions of years sitting in the ground, it doesn't go bad. It's the water from combustion or environment especially if plane tied down outside along with other byproducts that mixed with the oil that makes it bad.

[Raptor05121]

The real killer is the acid in the blow-by will slowly eat away at engines that don't fly long.

[neilpilot]

If I was not cutting open my filters I would be checking that screen more often.

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I'm sure your realize that the screen will catch those big pieces, and it's entirely possible to load the screen with internal part fragments and see little or no metal in the filter.  In other words, checking the filter is not a substitute for checking the screen.  Having said that, I'm also guilty of checking the screen only once every 75-100 hours.  

Edited September 8, 2015 by neilpilot

[RobertGary1]

The crush washer is just a few bucks at Aircraft Spruce. At annual you're making a big Spruce order anyway for basic annual supplies, this just gets tossed in with that.

 

-Robert

[N201MKTurbo]

I sometimes do an express oil change (change the oil without the filter). I can do the express without taking off the cowl. Just reach up through the cowl flap and attach the drain hose. If you let it drain overnight it will completely drain the oil filter. I had a trip last weekend and my oil was due. My annual is next month and I will change the oil and filter then. It seems like a waste to change the filter for the few hours I will fly in the next month.

The oil filter, like all filters get better at filtering the longer you leave them in service. The problem happens when the pressure drop across the filter gets so high that they bypass or rupture. I believe it would take hundreds of hours before an aviation oil filter would get to that state under normal circumstances.

[RobertGary1]

Lycoming and Mooney specify the filter change every 50 hours. But I doubt many of us get 50 hours on our oil. Oil is changed every 6 months. So it's common to change the oil without changing the filter. No requirement to change oil or filter at annual. It may be convenient but it's not required. 

 

-Robert