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Oil leak 912ULS

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peterthomson

Joined: 18 Jul 2010
Posts: 41
Location: Thailand

Posted: Tue Feb 19, 2013 8:12 am Post subject: Oil leak 912ULS

Hi Listers 

I have a very slight oil leak somewhere near the lower front of the engine. 

Not enough to show in oil usage - at 850hrs still does not use oil between 50hr changes. 

But enough to run oil underneath the engine and also be picked up in the prop stream and lay a fine film over the top RHS of the engine (and fuel and ignition components which live there) and inside  the RHS of the cowling.  

It does not appear to be from the oil pressure sensor fitting or the oil pressure spring unit, both of which I have changed prior to the leak. Nor from the flange fittings of the oil pump housing. Nor the hardened gasket of the fuel pump.  

Could it be the crankcase join?  

Could oil move forward along the bottom of the crankcase in flight - air movement would indicate otherwise?  

All comments most welcome! 

Peter

 CH701/912ULS  [quote][b]

rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Tue Feb 19, 2013 9:28 am Post subject: Oil leak 912ULS

Peter, Probably the easiest way to find your leak is with a phosphorescent die and a black light. http://www.tracerproducts.com/

is there anything that Amazon doesn't carry?

  http://www.amazon.com/Tracer-Products-TP34000601-Fluorescent-Detection/dp/B000JFHNTM

 Rick Girard



 On Tue, Feb 19, 2013 at 10:12 AM, Peter Thomson <peterlthomson(at)gmail.com (peterlthomson(at)gmail.com)> wrote:

 	  Quote: 	
		    

Hi Listers 

I have a very slight oil leak somewhere near the lower front of the engine. 

Not enough to show in oil usage - at 850hrs still does not use oil between 50hr changes. 

But enough to run oil underneath the engine and also be picked up in the prop stream and lay a fine film over the top RHS of the engine (and fuel and ignition components which live there) and inside  the RHS of the cowling.    

It does not appear to be from the oil pressure sensor fitting or the oil pressure spring unit, both of which I have changed prior to the leak. Nor from the flange fittings of the oil pump housing. Nor the hardened gasket of the fuel pump.    

Could it be the crankcase join?  

Could oil move forward along the bottom of the crankcase in flight - air movement would indicate otherwise?  

All comments most welcome! 

Peter

 CH701/912ULS   	  Quote: 	
		  



ist" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List

tp://forums.matronics.com

_blank">http://www.matronics.com/contribution



	
	




-- 

Zulu Delta

Mk IIIC

Thanks, Homer GBYM

It isn't necessary to have relatives in Kansas City in order to be unhappy.

    - Groucho Marx

 

  [quote][b]

_________________
The smallest miracle right in front of you is enough to make you happy....

dpark748(at)hotmail.co.uk
Guest

Posted: Tue Feb 19, 2013 9:37 am Post subject: Oil leak 912ULS

I had a similar leak during test flying, found it was the oil pressure sender not screwed in tight enough?

Dave



Sent from my iPad



On 19 Feb 2013, at 16:20, "Peter Thomson" <peterlthomson(at)gmail.com> wrote:



[quote] Hi Listers

 

 I have a very slight oil leak somewhere near the lower front of the engine

joeing701(at)simnet.is
Guest

Posted: Tue Feb 19, 2013 9:50 am Post subject: Oil leak 912ULS

Hello Peter.I had a small oil leak on one of the hoses for the oil cooler. The cooler is underneath the radiator.

Just a loose clamp. I would check that area and eliminate the hoses?

Hope this will help.

Johann G.

Iceland.

CH701 Rotax 912UL.



On 19.2.2013, at 16:12, Peter Thomson wrote:

[quote]

Hi Listers

I have a very slight oil leak somewhere near the lower front of the engine.

Not enough to show in oil usage - at 850hrs still does not use oil between 50hr changes.

But enough to run oil underneath the engine and also be picked up in the prop stream and lay a fine film over the top RHS of the engine (and fuel and ignition components which live there) and inside  the RHS of the cowling.

It does not appear to be from the oil pressure sensor fitting or the oil pressure spring unit, both of which I have changed prior to the leak. Nor from the flange fittings of the oil pump housing. Nor the hardened gasket of the fuel pump.

Could it be the crankcase join? 

Could oil move forward along the bottom of the crankcase in flight - air movement would indicate otherwise? 

All comments most welcome!

Peter

 CH701/912ULS   	  Quote: 	
		  



href="http://www.matronics.com/Navigator?RotaxEngines-List">http://www.matronics.com/Navigator?RotaxEngines-List

href="http://forums.matronics.com/">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/contribution



	
[b]

peteohms

Joined: 31 Oct 2007
Posts: 224
Location: Leander, TX

Posted: Tue Feb 19, 2013 10:17 am Post subject: Oil leak 912ULS

Peter,



I have an old 912 (1991).  I found that the oil streaming out under my Kitfox adds about 5 mph to my airspeed.  Like squeezing a watermelon seed between your fingers.  



Pete

Leander, Tx



On Feb 19, 2013, at 10:12 AM, Peter Thomson <peterlthomson(at)gmail.com> wrote:



[quote] Hi Listers

 

 I have a very slight oil leak somewhere near the lower front of the engine

_________________
Pete
Leander, TX
Kitfox III, 912ul, Grove

Vic Peters

Joined: 30 Oct 2009
Posts: 54
Location: Millinocket, Maine

Posted: Tue Feb 19, 2013 11:59 am Post subject: Oil leak 912ULS

Peter

 Had the same prob. Had a film on certain  things.

 Changed my oil tank/cooler large  oring.

 No film

   [quote][b]

_________________
Vic
912ul Xtra
Maine
Too old to cut the mustard but not the cheese.

mortweaver(at)sbcglobal.n
Guest

Posted: Tue Feb 19, 2013 12:42 pm Post subject: Oil leak 912ULS

I routinely inspect for 912 valve cover and push rod tube seepage by reaching under the engine and touch those locations.  If I pull back oily fingers then I can assess as to the degree of seepage.  During the first 100 hours of operation, I did confirm two engine case seam leaks and one push rod tube thread leak at cylinder head intersection.  I avoided major engine tear down by applying 3M Fire Barrier high temp silicone (structural grade RTV).  The surfaces were cleaned initially with MEK before application of silicone.  I have since logged over 200 hours on the engine with no new leaks in those locations.  I used the same silicone to mount the coolant radiator.  For a low oil pressure leak, I thought it just might work....I was right.  

 Dave Weaver N912GR 



--- On Tue, 2/19/13, Richard Girard <aslsa.rng(at)gmail.com> wrote:



  	  Quote: 	
		  

From: Richard Girard <aslsa.rng(at)gmail.com>

Subject: Re: Oil leak 912ULS

To: rotaxengines-list(at)matronics.com

Date: Tuesday, February 19, 2013, 11:27 AM



 Peter, Probably the easiest way to find your leak is with a phosphorescent die and a black light.   http://www.tracerproducts.com/

 is there anything that Amazon doesn't carry?

 http://www.amazon.com/Tracer-Products-TP34000601-Fluorescent-Detection/dp/B000JFHNTM

 



 Rick Girard



 On Tue, Feb 19, 2013 at 10:12 AM, Peter Thomson <peterlthomson(at)gmail.com (peterlthomson(at)gmail.com)> wrote:

  	  Quote: 	
		   Hi Listers

 I have a very slight oil leak somewhere near the lower front of the engine.

 Not enough to show in oil usage - at 850hrs still does not use oil between 50hr changes.

 But enough to run oil underneath the engine and also be picked up in the prop stream and lay a fine film over the top RHS of the engine (and fuel and ignition components which live there) and inside  the RHS of the cowling.

 It does not appear to be from the oil pressure sensor fitting or the oil pressure spring unit, both of which I have changed prior to the leak. Nor from the flange fittings of the oil pump housing. Nor the hardened gasket of the fuel pump.

 Could it be the crankcase join? 

 Could oil move forward along the bottom of the crankcase in flight - air movement would indicate otherwise? 

 All comments most welcome!

 Peter

CH701/912ULS

 	  Quote: 	
		  



ist" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List

tp://forums.matronics.com

_blank">http://www.matronics.com/contribution



	
	




 



-- 

 Zulu Delta

 Mk IIIC

 Thanks, Homer GBYM

 



 It isn't necessary to have relatives in Kansas City in order to be unhappy.

  - Groucho Marx

 

 	  Quote: 	
		  



ist" rel=nofollow target=_blank>http://www.matronics.com/Navigator?RotaxEngines-List

et=_blank>http://forums.matronics.com

llow target=_blank>http://www.matronics.com/contribution



	


	
 [quote][b]

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Wed Feb 20, 2013 5:22 am Post subject: Re: Oil leak 912ULS

I had a small nuisance oil leak somewhere in the front of the 912-F3 (1100+ hours) in my Katana last summer. It was not enough to ground the airplane. The leak would not appear on full power ground run-up but only after flying. After many many hours of one-at-a-time removal of everything possible, including gearbox, inspection, re-installing, and test-flying, I found two leaks. One was the fuel pump gasket and the other was the oil pressure sending unit joint where it threads into the oil pump. 



The fuel pump gasket, upon inspection did have a bad spot on it and replacing that stopped that particular leak. I suspect that gasket/spacer was damaged at some point during service when it is removed to check fuel pump cam in gearbox. 



On the oil pressure sending unit, during prior service (before the leak discovery) I had been careful to re-torque to spec the NPT threaded fitting into the fuel pump. Apparently the "correct" torque spec is not enough to seal at this joint, but since that was the only possible source left, I tightened it up about 1/2 turn more and that stopped it. I'd hate to tighten it too much and crack the oil pump housing $$$$$.

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Wed Feb 20, 2013 5:55 am Post subject: Re: Oil leak 912ULS

Hi Peter,



If it is on the very front of the engine then and this is a tractor prop then it isn't a valve cover seep because it won't go to the front of the engine, but farther back.  If it's on the right side it isn't the oil filter. The oil pump housing rarely leaks, but I wouldn't rule it out totally. 

I would clean the engine and then sit for 30 min. and let it run at 4000 rpm on the ground. The problem with an in flight check is the high pressure air over the engine tends to spread it too much and make it hard to find. If you still can't find it spray some foot powder on the front of the engine and any leak will show up like a red flag.

The most common are:

1. The bottom of the gearbox. It would need removal and re-sealed. It 

    isn't hard to do.Re-seal it with Loctite 5910 (European) or 598 (US) or 

    Permatex "The Right Stuff".

2. It it is the older AC or Pierberg fuel pump then it is coming out of the  

    weep hole on the bottom of the pump and will need a new pump. (very 

    common) I'll be doing this very thing this morning. A new pump is 

    $171.

Other less likely are the oil pressure sender that was loose, but if it was tight to start with probably isn't the issue. Any oil cooler fittings up front, even if they look clean put a wrench on them or check the hose clamps. The high pressure air flow pushes it off the fitting towards the back and gives you a false location.

My money is still on the first two common if this just started to leak and wasn't before.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

peterthomson

Joined: 18 Jul 2010
Posts: 41
Location: Thailand

Posted: Wed Feb 20, 2013 4:56 pm Post subject: Oil leak 912ULS

Many thanks to all who gave a wealth of information on finding this. I WILL track it down and post result !

  [quote][b]

peterthomson

Joined: 18 Jul 2010
Posts: 41
Location: Thailand

Posted: Thu Feb 21, 2013 1:42 am Post subject: Oil leak 912ULS

Well, I tried Roger's idea of cleaning things up and ground running at 4000rpm.



Before this, I resealed the threads on oil pressure sensor and oil pressure spring threads with Loctite 567.



After ground run, I found the leak - slightly forward of the first Allen screw on the bottom of the crankcase, where the two halves join - it is a point where the crankcase starts to slope up. The seal, Rotax recommends Loctite 574, a silicone material, must have let go at that point (after about 8 years and 800hrs...).

 

The Loctite guy here recommends Loctite 290, to wick into the gap and likely seal it. Good fortune that it was not further back and hard to get at 



Thanks again for all the comments !



  [quote][b]

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