An Engines Mission?

[Mcstealth]

Is it an aviation engines mission to drip oil? I have now been associated with  both a four and six cylinder Lycoming for a few months now. They both make a mess. Take the panels off, and it's a mess inside. Clean it up, go fly a couple of hours and I can't tell the exact location of the leak. ARRGH!!!

[A64Pilot]

I’ve often heard Lycomings leak, but that’s not been my experience, my current motor doesn’t and the 540 I overhauled didn’t either.

But the 540 may have had 500 hours on it when I sold it and my 360 has about 300, so that may not be a fair comparison. I don’t remember if the 540 did before I overhauled it, but it had been apart for a prop strike too.

Edited May 13, 2022 by A64Pilot

[EricJ]

7 hours ago, Mcstealth said:

Is it an aviation engines mission to drip oil? I have now been associated with  both a four and six cylinder Lycoming for a few months now. They both make a mess. Take the panels off, and it's a mess inside. Clean it up, go fly a couple of hours and I can't tell the exact location of the leak. ARRGH!!!

That sounds excessive.   If it is leaking that much there is likely an issue that needs attention.    Either the talcum powder or oil dye methods might be useful just running it on the ground a bit if it's that bad.

I had a messy leak that I couldn't find and eventually the prop governor self-identified as the source.    Now it runs pretty clean.

[Shadrach]

I would rule out a case crack.  Lycomings don’t drip oil for no reason

[Hank]

Don't forget the oil filler tube. It can unscrew a tiny bit and leak. There's an o-ring down there, too.

[GeeBee]

On 5/13/2022 at 11:29 AM, Mcstealth said:

Is it an aviation engines mission to drip oil? I have now been associated with  both a four and six cylinder Lycoming for a few months now. They both make a mess. Take the panels off, and it's a mess inside. Clean it up, go fly a couple of hours and I can't tell the exact location of the leak. ARRGH!!!

Short answer is yes. 90 year old technology, what do you expect?

[Mooney Dog]

On 5/13/2022 at 10:29 AM, Mcstealth said:

Is it an aviation engines mission to drip oil? I have now been associated with  both a four and six cylinder Lycoming for a few months now. They both make a mess. Take the panels off, and it's a mess inside. Clean it up, go fly a couple of hours and I can't tell the exact location of the leak. ARRGH!!!

If there's no oil under them, there's no oil in them!

 

you might check the prop governor, thats where mine started to leak. The oil lines to the cooler also might have a small leak.

Remember a small bit of oil looks like a whole quart. 

[Yetti]

It's just how they mark their spot.   I mean they have an oil breather tube on them so it's kind of by design.  You can look at it as free corrosion protection for the belly.

Edited May 16, 2022 by Yetti

[0TreeLemur]

On 5/13/2022 at 11:03 PM, Hank said:

Don't forget the oil filler tube. It can unscrew a tiny bit and leak. There's an o-ring down there, too.

Hank makes an excellent point.  I raised the wet oil-pan and carbonized residue on the muffler shroud with my A&P during this annual.  He showed me how the oil filler tube is loose,  letting oil leak out and cause all that messiness.    That's the only sign of an oil leak he found.

A comic I read years ago showed a car sitting over a puddle on a used car lot.  The salesman said "That's not oil, that sweat from all that horsepower".

[Mcstealth]

On 5/13/2022 at 11:03 PM, Hank said:

Don't forget the oil filler tube. It can unscrew a tiny bit and leak. There's an o-ring down there, too.

Started the 100hr inspection. Two weak cylinders but that is a different topic. With the cowl off, damn if I wasn't able to tighten the filler tube an 1/8th or so. The tube  is safety wired but it was certainly loose nonetheless. 

Thanks

David

 

 

[Skates97]

On 5/13/2022 at 9:03 PM, Hank said:

Don't forget the oil filler tube. It can unscrew a tiny bit and leak. There's an o-ring down there, too.

 

5 minutes ago, Mcstealth said:

Started the 100hr inspection. Two weak cylinders but that is a different topic. With the cowl off, damn if I wasn't able to tighten the filler tube an 1/8th or so. The tube  is safety wired but it was certainly loose nonetheless. 

Thanks

David

They make a silicone gasket which does much better, just do not over tighten it.

https://www.aircraftspruce.com/catalog/eppages/basegasket.php

My O-360 has had various leaks over the 5 1/2 years I have had it but I have always been able to eventually track them down and eliminate them. I don't fall in the "they all leak" camp, even with high hours. Mine is almost to 2,100 hours and currently (finds a piece of wood to knock on) not leaking and hasn't for the past 5-6 months. The last leak was a stripped clamp on the oil return line from the #3 cylinder. Didn't do enough to be obvious but just enough to annoy me.