Oil leak around oil pick up line

[Shiroyuki]

Hi everyone, I’m having a oil leak issue on my way home and lost about 1 qt of oil during a 2.7 hours flight.

The engine was field overhauled last year during annual inspection and have roughly 80 hours so far on it.

The mechanic found a drip of oil hanging on the brass rasher, supposedly a crush washer at the oil pick-up screen. It was removed and reinstalled with new crush washer twice but the leak still persist. Then we suspects the oil is coming from the oil sump gasket just above it, and added some epoxy sealant and did a test flight, and it is still leaking. None of these two action made any changes to the oil leak symptom.

The mechanics couldn’t find any leak during ground run up, and every test flight ends with oil covering the gear door. Most oil is on the left gear door but a few lines on the right gear door too. We can see oil on hoses and engine mounts below that brass crush washer so that area must be where it comes from.

it is bone dry above the engine sump gasket, and oil everywhere below the oil pick up line washer.

Now I’m not at my home field and my usual mechanic is six hour flight away. The local guys straight up gives up and says they couldn’t find any leak, and says i should fly it to my mechanic and get it sorted out. I’m a bit concerned about the oil leak getting worse in flight. The leaked oil is also dripping onto exhaust pipes making a very nasty smell.

Does anyone have any similar experience about an oil leak around this area?

 

[Slick Nick]

I would not fly it until you get the leak fixed. Its one thing to throw 8 quarts in it if your shop is 20 minutes away, it's another to try and fly 6 hours.

I mean, it's gotta be coming from SOMEWHERE. Where is the plane currently? If you're in Alberta I may be able to help.

[N201MKTurbo]

It’s really hard to tell from the pic you sent, but I would look at the prop governor. It can drip down there and it would only leak while running. When they leak, they usually leak a lot because of the high pressure.

[Shiroyuki]

33 minutes ago, N201MKTurbo said:

It’s really hard to tell from the pic you sent, but I would look at the prop governor. It can drip down there and it would only leak while running. When they leak, they usually leak a lot because of the high pressure.

The prop governor appears to be clear of oil, couldn’t find any drips around it.

[Shiroyuki]

2 hours ago, Slick Nick said:

I would not fly it until you get the leak fixed. Its one thing to throw 8 quarts in it if your shop is 20 minutes away, it's another to try and fly 6 hours.

I mean, it's gotta be coming from SOMEWHERE. Where is the plane currently? If you're in Alberta I may be able to help.

Yorkton SK.

I actually started my trip in Springbank with Rocky Mountain aircraft. They were doing some clean up after an avionic installation and did my last annual inspection last month. The noticed the oil leak and they also thought it comes from the oil pick up screen. They tightened it and did a ground run with no leak found, and sent me on my way…

[EricJ]

19 minutes ago, Shiroyuki said:

The prop governor appears to be clear of oil, couldn’t find any drips around it.

My governor had an odd leak where it leaked from the control input shaft, that the prop cable connects to.    It apparently only leaked at certain positions, since it didn't always do it.    I only figured that out because the governor failed and the prop shop saw it when they were testing it.   The leak went away with the new governor, so that fixed it.

Weepy oil leaks can be hard to find.   You can try tricks like putting talcum or baby powder around the area and see where it's not dry, or putting fluorescent dye in the oil (which is harmless) and a UV lamp to find the oil.    I've not had great success with the dye, but others have.    Everything needs to be pretty clean to start with for either of those to work well.

[Bartman]

Clean it up with mineral spirits in a cheap garden sprayer. Get the dye and black light at auto parts store. Run the engine for a short time and cycle the prop, then look for leaks. If none seen, fly one trip around the pattern and look for leaks. You will find it. 

[Skates97]

4 minutes ago, Bartman said:

Clean it up with mineral spirits in a cheap garden sprayer. Get the dye and black light at auto parts store. Run the engine for a short time and cycle the prop, then look for leaks. If none seen, fly one trip around the pattern and look for leaks. You will find it. 

This works. We were trying to find a leak, main place I saw it was in flight it would have a little coming out of the top of the cowl opening and back across the cowl with some drops hitting the windscreen. Cleaning the engine, dye in the oil, on e trip around the pattern, and black light showed it was the oil quick drain. Yes, some reverse air flow inside the cowl. 

If you fly it with the dye only make one trip around the pattern. Any more than that and it will blow everywhere inside making it hard to pinpoint. 

[Fritz1]

As stated before, clean real good with mineral spirits, use baby powder or white dye penetrant developer spray, run enough to develop the leak, ground run may not be enough, probably a trip around the pattern will be required, land, pop the cowl and analyze the oil flow pattern, you may need two or three clean ups and test runs to really figure it out. When you are confident you fixed it, fly for 30 min and then verify leak is gone. Persistence kills any leak!

[Slick Nick]

10 hours ago, Shiroyuki said:

Yorkton SK.

I actually started my trip in Springbank with Rocky Mountain aircraft. They were doing some clean up after an avionic installation and did my last annual inspection last month. The noticed the oil leak and they also thought it comes from the oil pick up screen. They tightened it and did a ground run with no leak found, and sent me on my way…

Mustang maintenance does all of my work. They are outstanding. Highly recommend. 

[Bartman]

23 hours ago, Shiroyuki said:

Yorkton SK.

I actually started my trip in Springbank with Rocky Mountain aircraft. They were doing some clean up after an avionic installation and did my last annual inspection last month. The noticed the oil leak and they also thought it comes from the oil pick up screen. They tightened it and did a ground run with no leak found, and sent me on my way…

I had a leak at the oil screen once immediately after an oil change. There is a crush washer under that cap and it didn’t get crushed all the way. Since it was immediately after an oil change we tightened and I got some extra practice on safety wiring that cap. It didn’t leak again but I pulled the screen and installed a new crush washer next oil change. 

[Shiroyuki]

4 minutes ago, Bartman said:

I had a leak at the oil screen once immediately after an oil change. There is a crush washer under that cap and it didn’t get crushed all the way. Since it was immediately after an oil change we tightened and I got some extra practice on safety wiring that cap. It didn’t leak again but I pulled the screen and installed a new crush washer next oil change. 

That crush washer is our first suspect. We’ve tighten it twice so far with another attempt to replace it with a new crush washer, and it still leaks. Either these mechanic I’m dealing with away from home is incompetent, or that’s not where the leak is from…

My own mechanic is now telling me to check the vernathrm valve which is just below the oil filter, but I’ve gave up already.

Flew the plane home on a three hour flight with a stop halfway yesterday and lost about hall a quart of oil. Whatever is leaking, isn't actually leaking a huge amount of oil. It just makes a huge mess.

I’m going to call the engine shop that did an field overhaul on it only 80 hours ago and see what they think on Tuesday, when Canadian thanksgiving is over, and then decide if I want to fly the plane to Toronto or Montreal to get this leak fixed.

[Slick Nick]

Hows' your dipstick tube? I've seen leaks at the bottom seal there before. If the dipstick is in too tight and the tube isn't lockwired properly, unscrewing the dipstick can actually loosen the tube a bit and cause a leak at the bottom. Can be fixed with a new O-ring and tightening the lockwire on the tube.

[PT20J]

That crush washer is not crushed by torque but by turning the bolt 135 degrees. If it leaks I would remove the screen check the mating surfaces and install a new washer and tighten it properly.

[Shiroyuki]

On 10/13/2024 at 9:03 AM, Slick Nick said:

Hows' your dipstick tube? I've seen leaks at the bottom seal there before. If the dipstick is in too tight and the tube isn't lockwired properly, unscrewing the dipstick can actually loosen the tube a bit and cause a leak at the bottom. Can be fixed with a new O-ring and tightening the lockwire on the tube.

The dipstick was re-tightened with a new gasket during my recent annual in september. I don't see any oil at the bottom of the dipstick tube so I suppose it isn't leaking.

[Shiroyuki]

On 10/13/2024 at 10:43 AM, PT20J said:

That crush washer is not crushed by torque but by turning the bolt 135 degrees. If it leaks I would remove the screen check the mating surfaces and install a new washer and tighten it properly.

Can you elaborate on how it is suppose to tightened a bit more? Non of these mechanic I worked with are mooney mechanics, and they mostly works on turbine aircraft. I wouldn't be surprised if they didn't tighten it properly.

Is it supposed to be torqued to a specific torque, then add another 135 degree after that? I will confirm with those mechanic on how they tightened the crush washer.

[PT20J]

24 minutes ago, Shiroyuki said:

Can you elaborate on how it is suppose to tightened a bit more? Non of these mechanic I worked with are mooney mechanics, and they mostly works on turbine aircraft. I wouldn't be surprised if they didn't tighten it properly.

Is it supposed to be torqued to a specific torque, then add another 135 degree after that? I will confirm with those mechanic on how they tightened the crush washer.

It's not Mooney specific. It's a Lycoming spec. Reference Lycoming SSP-1776 Table of Limits and Torques. You turn the plug until the surfaces meet and then tighten by turning an addional 135 degrees.

[Shiroyuki]

1 minute ago, PT20J said:

It's not Mooney specific. It's a Lycoming spec. Reference Lycoming SSP-1776 Table of Limits and Torques. You turn the plug until the surfaces meet and then tighten by turning an addional 135 degrees.

I will confirm with the mechanics tomorrow how they tightened that crush washer, when canadian thanksgiving is over.

Both shops mostly works on PT6 equipped aircraft like Air Tractors and Twin Otters. So they might not know.

[Slick Nick]

Can I ask why you took your Mooney to Rocky Mountain for an annual when there are about 4 other (better) shops at Springbank? 

[Shiroyuki]

4 minutes ago, Slick Nick said:

Can I ask why you took your Mooney to Rocky Mountain for an annual when there are about 4 other (better) shops at Springbank? 

Because I was planning to have a pair of garmin G5 installed and not much avionic shop can do both annual and avionic work.

I usually visit Oasis Aero in Minnesota which is much much closer to me (two hour comparing to a six hour flight) but they can't do annual on Canadian plane. I also have a mechanic that I used to work with when I still live in Toronto, he is very knowledgable about many different type of airplane. But his shop is pretty busy and turn around time can be longer than what I hoped.

[Shiroyuki]

8 minutes ago, Slick Nick said:

Can I ask why you took your Mooney to Rocky Mountain for an annual when there are about 4 other (better) shops at Springbank? 

I'm also not saying RMA is bad. They did an excellent job with the avionic install without going over the quote, and turned the plane around in only 2 weeks with a very extensive annual and avionic installation. They got a lot of things fixed and found some problems that I've long been suspecting, which some mechanic told me it is ok to leave it as is.

I previously had a bad experience with a avionic shop in Toronto which charge me with 100 hour in extra labour and a full extra month for basically the same installation. So I was looking for a different, more experienced shop to avoid something like that.

[MB65E]

Crush gaskets are not rocket science.

Solid side against the plug. Don’t smoke it on. Replace every time.

Your Sump isn’t even saftied. 
-Matt

[MikeOH]

Also, I believe the crush washer needs to be installed with the split side against the oil sump.  That's my recollection; you should verify!

[EricJ]

15 minutes ago, MikeOH said:

Also, I believe the crush washer needs to be installed with the split side against the oil sump.  That's my recollection; you should verify!

Yes, the solid side goes toward the rotating surface, i.e., the plug.

[MB65E]

Yeah, split side towards the component, or Solid side against the plug. 
However you want to remember it. 
 

-Matt