I just did an oil change and inspected the oil filter mat and noticed more than usual silver metal specks throughout the mat.


Here are more specifics:

  • RV-12 aircraft

  • 912 ULS engine - SN 6785021

  • 509 hours since new.  Engine operation has been normal.

  • 5 year rubber change out performed in March 2022. Oil purge successfully performed in accordance with SI-912-018. This is the first oil change since oil hoses were replaced.

  • Oil changed every 25 hours - Aeroshell Sport Plus 4 oil used since new

  • Oil analysis done almost every oil change. Oil analysis on this oil change had normal results.

  • Previous filter mat inspections normal (a few silver specks) so this change has happened in the last 25 hours.

  • 25 hours since last oil change - everything normal on previous oil changes

  • Metal on the filter mat is magnetic

  • Gearbox magnetic plug had very minor fuzz - same as previous inspections - normal

  • Even though the oil had 15 minutes ground run time since the oil change, I drained the oil again from the oil tank.  Oil was drained directly from the tank through a large coffee filter.  I did not see anything significant but there were a few sparkles, consistent in shape and size with what I saw on the oil filter mat but not in the same quantity.  None of it was visible to the naked eye but I did see some while viewing the coffee filter through a lighted magnifying glass. I also wiped out the bottom of the oil tank and it was clean, maybe saw a sparkle or two on the rag.

  • I refilled the oil tank, removed the upper spark plugs, and rotated the engine by hand until I got oil pressure.  While I had the spark plugs out, I put each cylinder at TDC and pulled the valve covers and checked the lifters.  All of the lifters were solid - no movement when pushing on the rocker arm at the pushrod end for about 3 seconds each.

Trying to decide on the next step.  Some experts that I have talked to said it's possible that accumulated metal (break-in metal, swarf, etc) has been lurking somewhere in the system (oil cooler for example) and worked it's way loose when the system was completely opened up during the rubber hose change out.

I'm leaning toward flying and then drain the oil and change the filter again in about 15 hours but checking here to see if there's anything else that I need to look at before I decide to fly. 

9272_1_IMG_0106.JPG (You do not have access to download this file.)
  • Re: Metal in Oil Filter

    by » 3 months ago

    I believe what you were told by some experts is very likely to be true. I agree with your plan to go ahead and fly for 10-15 hours and then drain/recheck the filter mat again. Your photo does not indicate to me anything catastrophic about to happen. A debris pocket probably got dislodged during the complete system drain.

  • Re: Metal in Oil Filter

    by » 3 months ago

    I wouldn’t worry either. I see this in quite a few engines. Just look at it again at the next oil change. I think since your magnetic plug was in good shape then I wouldn’t lose a lot of sleep over it.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

  • Re: Metal in Oil Filter

    by » 3 months ago

    Who does your oil analysis? If it’s Blackstone and they said it was normal, you have nothing to worry about.

  • Re: Metal in Oil Filter

    by » 3 months ago

    Appreciate all of the replies.  Yes, Blackstone Labs did the analysis.

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