Looking at a plane with about 400 hours on the engine since overhaul in 2021. Flown regularly the whole time since the overhaul so no time sitting. In the last several engine log entries it notes "trace metal found in oil filter." I'm no expert but my understanding is any metal coming from an engine is a bad sign, but it really doesn't make sense that such a fresh engine flown regularly would have issues. Is this actually common/something to not be concerned about? If I decide to move forward I'd get an extensive prebuy of course but just curious what people think of this? I've looked at logs of plenty of other aircraft with relatively fresh engines and haven't seen comments like that in the logs before so that's why I ask.
"Trace metal found" in recently overhauled engine logs
- Thread starter T Bird
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It depends more on how they define "trace metals." But in general most piston engines will have some minute metal particles in the filter at each oil change simply due to the nature of the engine. The key is the type, size, and amount of those particles. Perhaps review the OEMs recommendation on those particles to develop a base line. For example, here's Lycoming SB480 on the matter. As to the mx record entries, how they are written tend to be subjective to the person and should be viewed the same.
I hate it when metal gets into my logs.
Rcmutz
Pattern Altitude
I’d say, any mention of metal after several oil changes past the engine breakin, iis cause for further investigation as Bell206 suggests. Amount, and composition will tell you a lot. Could be a piston pin cap, a spun bearing, a deteriorating cam lobe, rings, etc, etc.Go here and take a look.
www.avweb.com
The Savvy Aviator #44: Making Metal
Recently, I heard from an aircraft owner who had just discovered something worrisome during an owner-assisted annual:
www.avweb.com
bonefishpete
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Who did the overhaul? Big name shop or Bob the local A&P? 400 hours is low time. If plane and price are favorable then have pre buy inspect filter again along with suction screen. Consider engine mid time and roll the dice.
Help to know make and model too.
Also figure some people won’t think twice before buying if price is on point. You may lose the buy.
Help to know make and model too.
Also figure some people won’t think twice before buying if price is on point. You may lose the buy.
It's normal to find a few flakes in the oil filter. I've rarely cut open an oil filter that didn't have what I'd describe as a trace; maybe 2 or 3 small flakes or whiskers. I usually write "no abnormalities" to avoid this very situation. I'm not saying don't ask the question, but I wouldn't outright dismiss the airplane over this. Take a look at that SB Bell linked above...it takes a LOT of metal to condemn an engine. Way more than you'd think, and way more than I'd be comfortable flying behind.
Jdm
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You can send Continental your AMS numbers for proper metal identification. I think Avlab are the only ones that offer AMS numbers. You can also send them your oil filter to pull these numbers. According to the SB that Bell provided, it appears that Lycoming offers a similar service.
Sierra1
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It’s terrible on your O-ring
brien23
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No big deal, engine failure that's why you practice emergency landings and good lawyers are for.
bonefishpete
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Would you be mad if your mechanic put this in your engine logbook? Be like doing an annual then putting all the discrepancies that weren’t fixed and didn’t have to be fixed for an airworthy plane in the planes logbooks.
SixPapaCharlie
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Every oil filter I have cut open for 10 years has had some glitter in it.
MauleSkinner
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You have daughters, right?
Daleandee
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Well I do have an advantage as I tell the mechanic exactly what I want written in the engine logbook and he does it ...
It's experimental and I'm the mechanic
Rcmutz
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Quit adding the magic pixie dust to your oil!
SixPapaCharlie
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That. But so many log entries state "no metal found", skewing our perception.
I asked my IA how will I know when the engine is "making metal". His reply was "you'll know it when you see it". A few months later he showed me the filter from an engine that was making metal - I understood what he meant. It was like looking at metallic paint mixed with oil.
Pinecone
Final Approach
Here is what the Lycoming Bulletin says, for those who don't want to read the whole thing.
"Size - “Chunks” are metallic particles larger than 3/16-inch in size; chips are smaller than chunks. Chunks
and chips require immediate analysis. Yet metallic particles can be small dust-size particulates - that is
where quantity becomes more of the issue in this case."
"Quantity – If more than five small particulates are on almost every panel in the oil filter element or if there is a 1/4 teaspoon full of metallic particles from an oil pressure screen or oil suction screen, these metallic particles require immediate analysis because they can be an indication of an engine component being worn or damaged."
More than 5 PER PANEL/PLEAT or MORE THAN 1/4 TEASPOON is OK. That is a LOT. So a few sparklies would be trace and not a worry unless the quantity starts to increase.
"Size - “Chunks” are metallic particles larger than 3/16-inch in size; chips are smaller than chunks. Chunks
and chips require immediate analysis. Yet metallic particles can be small dust-size particulates - that is
where quantity becomes more of the issue in this case."
"Quantity – If more than five small particulates are on almost every panel in the oil filter element or if there is a 1/4 teaspoon full of metallic particles from an oil pressure screen or oil suction screen, these metallic particles require immediate analysis because they can be an indication of an engine component being worn or damaged."
More than 5 PER PANEL/PLEAT or MORE THAN 1/4 TEASPOON is OK. That is a LOT. So a few sparklies would be trace and not a worry unless the quantity starts to increase.
painless
Line Up and Wait
And that had me spitting out my coffee this morning. Funny stuff.
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There are places where particles like to hang out.
Metal from previous failures , cylinder and starter clutch changes know
those places. Too often the Oil Cooler and hoses are continued in service
after an event. They can show up years later.
Metal from previous failures , cylinder and starter clutch changes know
those places. Too often the Oil Cooler and hoses are continued in service
after an event. They can show up years later.
MauleSkinner
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For the record, your mechanic wouldn’t call you if your engine was making 10mm sockets…he’d sell them himself on the black market.
Daleandee
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From my limited experience, normal engine life goes from breaking in to wearing out. Between those two events there should be many hours of happy flying ...
An aircraft mechanic would know what to do with a 10mm socket.
MauleSkinner
Touchdown! Greaser!
A car mechanic might, but I’m not sure about an aircraft mechanic.
Daleandee
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A car mechanic might, but I’m not sure about an aircraft mechanic.
Sure he would he just calls it a 3/8 ...
If the log entry is honest, that is normal. The risk is that the filter was full of particles and he falsely reported it as "trace metal" to make it seem less bad in order to sell the airplane.
The Lycoming SB that @Bell206 linked is strongly recommended reading for anyone who is inspecting oil filters. Excellent advice & examples.
Yep, and this is normal for car oil filters too, at least cars used in amateur racing such as SCCA.
SoCal 182 Driver
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If the plane is between oil changes (e.g., has been flown 10 hours since the last oil change), ask the owner if you can drain a bit of oil and send it off to Blackstone. They'll let you know if there are unusual amounts of metal in the oil, and the types of metal. You may be dealing with an over-sharing A&P, and there's no problem, or the bits in the filter could be indicative of issues now, or forthcoming. An oil analysis will help you sort fact from fiction.
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UOA can give both false negatives (clean reports on engines that are making metal) and false positives (bad reports on healthy engines). That's not to say UOA is always entirely useless, only that it won't necessarily help in this or any other given situation. Especially a single UOA data point, since what value UOA can provide is mainly around trends over time, and even that is not completely reliable.
In summary, it's not a bad idea to take a sample and do UOA, it's inexpensive and won't hurt, even if it might not help either.