Oil leak vs Grease leak MT prop ?

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yl472401
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Oil leak vs Grease leak MT prop ?

Post by yl472401 »

I noticed spills from the front end of the front cowling and Co-pilot windshield since the oil change. From the beginning of thinking it could just be the residual from the oil spill from the oil change immediately prior to repeated happening several times after I wiped off the engine cowling and windshield in order to identify the continue existence of the problem. Did a night flight last night and determined it is a real problem and needs to be fixed. I did a little history search/research on DAN and somebody mentioned it could be the prop grease leak.
What's your thoughts and diagnosis ?
I don't quite understand why it just happened right after the fresh oil change, it has been fine before that. That makes me suspect its the shop didn't do a decent job or mishandled during the process. Would too much pulling force on the propeller blade or improper RPM handling (i.e. Rapid or prolonged change of RPM) cause the grease seal to be broken?
Thanks in advance.Image
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Last edited by yl472401 on Fri Dec 11, 2020 5:33 pm, edited 2 times in total.
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Re: Oil leak vs Grease leak MT prop ?

Post by yl472401 »

The oil pressure and temperature has been within green during the flights after the oil change.


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Re: Oil leak vs Grease leak MT prop ?

Post by Steve »

Bryan:

That looks like oil to me (and enough to be concerned about). Before my prop was overhauled about 7 years ago and had steel sleeves installed, it used to spit a tiny amount of grease every so often. The grease appeared as tiny black dots, which did not run like shown in your photos. I can't imagine how spillage during an oil change would wind up in that location. You could remove your spinner and determine where it is coming from...
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Re: Oil leak vs Grease leak MT prop ?

Post by yl472401 »

I texted these pictures to the shop and they are getting it back to inspect today.
... Man, if this kinda quality of work continues, it would make it really hard to get anything done at this place :roll:
Steve wrote:
Fri Dec 11, 2020 6:01 pm
Bryan:

That looks like oil to me (and enough to be concerned about). Before my prop was overhauled about 7 years ago and had steel sleeves installed, it used to spit a tiny amount of grease every so often. The grease appeared as tiny black dots, which did not run like shown in your photos. I can't imagine how spillage during an oil change would wind up in that location. You could remove your spinner and determine where it is coming from...
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Re: Oil leak vs Grease leak MT prop ?

Post by Steve »

Well, although the timing is suspect, I wouldn't blame the shop just yet. Like I said, I don't think it is related to the oil change. Having said that, oil changes are one of the preventive maintenance tasks an owner can legally perform...
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Re: Oil leak vs Grease leak MT prop ?

Post by Rich »

There is an o-ring that sits inside the crankshaft against the prop portion that inserts in there. This looks like a failure of that o-ring,
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Re: Oil leak vs Grease leak MT prop ?

Post by yl472401 »

Thanks Rich!
Could this be a easy fix?
Could this caused by mishandling of the prop plade, i.e. pulling on them to get the airplane move forward? I've seen it be done to other school planes constantly.

Rich wrote:
Fri Dec 11, 2020 6:45 pm
There is an o-ring that sits inside the crankshaft against the prop portion that inserts in there. This looks like a failure of that o-ring,
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Re: Oil leak vs Grease leak MT prop ?

Post by Steve »

yl472401 wrote:
Fri Dec 11, 2020 6:49 pm
Thanks Rich!
Could this be a easy fix?
Could this caused by mishandling of the prop plade, i.e. pulling on them to get the airplane move forward? I've seen it be done to other school planes constantly.
The O-ring is inside the prop hub, and the hub is bolted to the crankshaft with 6 large bolts (safety wired). Pulling on a blade isn't going to shift that at all. However, like any seal, it could develop a leak as the rubber compound ages and shrinks. It is easy to replace that O-ring, but the prop has to come off.
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Re: Oil leak vs Grease leak MT prop ?

Post by Rich »

R&R of the prop isn't a difficult job, but does require 2 people. It is tedious, as each of those trapped nuts can only be turned like 1-2 flats at a time, in turn.

Far better than an engine front seal failure would be.
2002 DA40: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Re: Oil leak vs Grease leak MT prop ?

Post by yl472401 »

Very informative. One more lesson learned. Thanks!! :D
Steve wrote:
Fri Dec 11, 2020 7:14 pm
yl472401 wrote:
Fri Dec 11, 2020 6:49 pm
Thanks Rich!
Could this be a easy fix?
Could this caused by mishandling of the prop plade, i.e. pulling on them to get the airplane move forward? I've seen it be done to other school planes constantly.
The O-ring is inside the prop hub, and the hub is bolted to the crankshaft with 6 large bolts (safety wired). Pulling on a blade isn't going to shift that at all. However, like any seal, it could develop a leak as the rubber compound ages and shrinks. It is easy to replace that O-ring, but the prop has to come off.

DSCN6025.jpg

DSCN6031.jpg
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