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Newbie Oil Change Question

Posted: Mon May 11, 2015 4:13 pm
by Onewinglo
My C145 has an oil filter, so do I still have an oil screen to remove and clean? I have an experienced helper lined up for my oil change but I want to show up with everything I need - such as crush washers, if I have an oil screen to remove in addition to the filter...
BTW I plan to switch to 50 Weight oil and install a new oil temp gauge soon.
Thanks,
JP

Re: Newbie Oil Change Question

Posted: Mon May 11, 2015 4:33 pm
by Bruce Fenstermacher
If you have the F&M filter adapter or the Cessna filter adapter, then for all practical purpose, you don't have a screen. But in reality you still do.
oil filter screens.png
The oil filter adapter replaces the fine screen #26, it does not replace the course screen #30. However this screen is so course it will only catch parts bigger than a broken pencil point. Many people don't inspect this screen, at least every oil change no mater if the have a oil filter or still the fine oil screen.

Caution should be used to insure you don't loosen the filter adapter when trying to loosing the filter, this is easy to do and leads to most troubles with the adapters.

Re: Newbie Oil Change Question

Posted: Mon May 11, 2015 7:49 pm
by Onewinglo
Thanks Guys for the repsponse. My local FBO has my oil filter and the Aeroshell 100W or the 100W Plus oil so it looks like I'll change oil this weekend. Looking forward to my first oil change - Woohoo!

Re: Newbie Oil Change Question

Posted: Mon May 11, 2015 9:29 pm
by 170C
I have never pulled the coarse screen since installing my F&M filter adapter. I have never heard anyone suggest that it should be done. I always liked the comment one of our members (forgotten who penned the phrase) posted that goes something like, "The coarse screen will only catch pieces large enough to have part numbers on them". :mrgreen:

Re: Newbie Oil Change Question

Posted: Tue May 12, 2015 2:12 pm
by cessna170bdriver
Less than a year into my ownership of 98C, someone suggested I check the coarse screen (the purpose of which is to protect the oil pump). I found a gear tooth in it. It turned out that the rear generator bearing had failed, allowing the drive gear to bounce in and out of engagement, breaking three teeth out of inner circle of the camshaft gear.

Recognizable parts shouldn't be in the screen; that's exactly why you should check for them...

Re: Newbie Oil Change Question

Posted: Tue May 12, 2015 3:53 pm
by DaveF
I check the suction screen on my Lycoming at every oil change. All it costs is a crush gasket, and it's a lot less work than cutting open the oil filter, which I'd also never consider skipping.

Re: Newbie Oil Change Question

Posted: Tue May 12, 2015 5:16 pm
by Onewinglo
Is the AN900-16 crush washer the correct size for the coarse screen?
Thanks,
JP

Re: Newbie Oil Change Question

Posted: Tue May 12, 2015 7:48 pm
by rusty
When 35D was overhauled the coarse screen is now replaced, with the fine screen. As part of a major the screen ( item #30 ) required to be replaced.

Re: Newbie Oil Change Question

Posted: Fri May 15, 2015 2:05 pm
by GAHorn
I was taught that is considered good practice (on piston engines) to check the coarse screen every 500 hrs, or anytime ferrous or large items found in the fine screen.
(Most turbine engines never check it except at major events such as overhaul or hot section. Some require an entirely NEW oil pump if the suction screen is ever opened up.)
I checked mine at 500 hrs, and will repeat at another 500. (Nothing found, and I have a spin-on filter which is always cut open for inspection. Anytime something is found in the fine screen or paper filter... then that something "got by" the coarse screen. I think MIles experience is extraordinary, and that frequent checking of the coarse screen exposes oneself to unnecessary risk (of contamination and breakage.)
Just my own O.