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Oil leak

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Yakman

Joined: 04 Feb 2012
Posts: 10
Location: Auckland New Zealand

Posted: Wed Dec 30, 2015 9:59 am Post subject: Oil leak

Morning everyone. Happy new year to you all.



My 18t appears to have developed an oil leak. I arrived at the hangar to find oil dripping from the bottom of the cowl, not a big leak but it's never done this in the 5 years I've owned it. Rather 

than reinventing the wheel, are there some common areas I should 

look first? Oil pressure is normal and it certainly doesn't squirt 

out when I start it.

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cjpilot710(at)aol.com
Guest

Posted: Wed Dec 30, 2015 11:34 am Post subject: Oil leak

The first questions to ask.

 1.How long was the airplane sitting?

 2.If the oil was just coming off the cowling, where inside the cowling was  it coming from?

  

 An airplane that sits for a long time can have oil fillup up inside  the engine because gravity is slowly draining it out of the tank, which sits  higher that the engine sump.  When the sump fills up, the oil "spills over"  into the #5 & #6 cylinders.  If the exhaust valve happen to be open,  enough oil can flow into the exhaust system.  When you pull the prop though  before starting, and oil comes out of the exhaust stacks, this is what's  happened.  (Note: There is a check valve in the oil pump that is suppose to  keep oil from flowing into the engine from the tank.  It often does not do  so.).  This is the reason you can get a "hydraulic lock" in those bottom  cylinders and thus the importance of pulling the prop though before  starting.  

  

 Also oil just dripping out of the cowling, could be the accumulation a  number of small oil leaks.  Hence they flow off the engine from various  places, on to the inside of the cowling, then to the floor.  You can have  leaks from push rod tubes, rocker box covers (18 of them), any of the gaskets of  the various bolt on units.

  

 The best (for me anyway) way catch leaks, is to remove the cowling.   Clean the engine and I mean REALLY CLEAN.  There are many different ways of  doing this however what I do, is mix liquid GUNK with thinner - (1/4 GUNK) and  spray it on the engine with a good sprayer.  Higher pressure will knock of  the heaver crap. You might a stiff narrow brush to get rid of some stains.   Let sit 15 minutes than wash off with water.  (It will not kill your  grass).  Let the engine dry off.  Then run it a good 5 minutes, do a  quick power check, and then shut down.  Then look for leaks.  Check  particularly around the base of the engine where the oil sump attaches.  If  you find oil leaks simply tighten up the nuts first.  Some places you may  need to replace gaskets.  WARNING;  If you find oil leaks at the very  base of the push rod tubes, DO NOT try to replace the "O" rings underneath where  the housing is bolted to the case.  Simply tighten the 2 nuts AND  LET IT BE.

  

 That about it.  Others on this list can add to this I am sure.

  

 Jim "Pappy" Goolsby

  

  

  

  In a message dated 12/30/2015 1:02:55 P.M. Eastern Standard Time,  Andrew.park(at)xtra.co.nz writes:

  	  Quote: 	
		  -->    Yak-List message posted by: "Yakman"    <Andrew.park(at)xtra.co.nz>



Morning everyone. Happy new year to you    all.



My 18t appears to have developed an oil leak. I arrived at the    hangar to find oil dripping from the bottom of the cowl, not a big leak but    it's never done this in the 5 years I've owned it. Rather 

than reinventing    the wheel, are there some common areas I should 

look first? Oil pressure    is normal and it certainly doesn't squirt 

out when I start    it.





Read this topic online    here:



http://forums.matronics.com/viewtopic.php?p=451516#451516===============================================

_nbsp;             (And Get Some AWESOME FREE     to find   Gifts       nbsp; List  k you for  p;                        -Matt Dralle,    List  ========================  e  ties  Day  ================================================               - MATRONICS WEB FORUMS  ================================================             - List Contribution Web Site  sp;                             ===================================================

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Vic

Joined: 12 Aug 2008
Posts: 115
Location: Southern Bavaria

Posted: Wed Dec 30, 2015 12:57 pm Post subject: Re: Oil leak

Hi,

maybe you want to check the small tap on the oil tank between the bottom cylinders. You will have to lap the taper with very fine grit to seal it. But certainly there are quite a few other places that can leak. Clean all places and check in short intervals for fresh leaks. Oil can travel long distances in time so look often.



   Vic

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Viperdoc

Joined: 19 Apr 2014
Posts: 484
Location: 08A

Posted: Wed Dec 30, 2015 4:40 pm Post subject: Oil leak

First question, where are you seeing oil pooled? Are Intake drains installed? Are the intake and exhaust collars tight? Hoses all tight? Any breaks in fabric wraps on the lines? Any oil around oil pressure sending unit on the firewall? The small oil pressure fabric covered hose from the transducer to the oil pump is somewhat ignored on occasion when the hoses have been replaced so it maybe more worn. The lines to the oil cooler in the wing root is likewise. Also welds on the capillaries in the oil cooler can break with wear and tear. Rare but can as well as gelling the oil in 0 degree weather can blow the cooler if the bypass valve fails. That generally makes a Hugh oil pool on the ramp or hanger floor when that happens though. Some a/c have had them removed.

So it is back to the first question. Where are you seeing oil pooled under the A/C? Having the prop positioned just right on the the #6 cylinder mostly but 5 &7 can leak oil also if the a/c has sat for a week especially if the shut off valve in the oil pump is slugged. Lastly the tank can spring a leak from the seams as well as the seams on the air oil separated can wear and leak. Granted this is rare too. 

Don't overlook your inverted oil return hoses also. 

Doc



Sent from my iPad



 	  Quote: 	
		   On Dec 30, 2015, at 11:59 AM, Yakman <Andrew.park(at)xtra.co.nz> wrote:

 

 

 

 Morning everyone. Happy new year to you all.

 

 My 18t appears to have developed an oil leak. I arrived at the hangar to find oil dripping from the bottom of the cowl, not a big leak but it's never done this in the 5 years I've owned it. Rather 

 than reinventing the wheel, are there some common areas I should 

 look first? Oil pressure is normal and it certainly doesn't squirt 

 out when I start it.

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=451516#451516

- The Matronics Yak-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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_________________
Viperdoc

Viperdoc

Joined: 19 Apr 2014
Posts: 484
Location: 08A

Posted: Wed Dec 30, 2015 4:53 pm Post subject: Oil leak

Wish I had seen your post before I did my post. Excellent summary. Was not going to address the push rod boots. They do not want to go there unless they have a split boot. 

Rare. Also the crush washers on the rocker arm axle can be a pesky source but not a source of  a big pool on the floor though. If the valve covers were pulled and the seal not  seated well when the cover was replaced can be a leak source too. 

Doc



Sent from my iPad



On Dec 30, 2015, at 1:32 PM, cjpilot710(at)aol.com (cjpilot710(at)aol.com) wrote:

 	  Quote: 	
		       The first questions to ask.

 1.How long was the airplane sitting?

 2.If the oil was just coming off the cowling, where inside the cowling was  it coming from?

  

 An airplane that sits for a long time can have oil fillup up inside  the engine because gravity is slowly draining it out of the tank, which sits  higher that the engine sump.  When the sump fills up, the oil "spills over"  into the #5 & #6 cylinders.  If the exhaust valve happen to be open,  enough oil can flow into the exhaust system.  When you pull the prop though  before starting, and oil comes out of the exhaust stacks, this is what's  happened.  (Note: There is a check valve in the oil pump that is suppose to  keep oil from flowing into the engine from the tank.  It often does not do  so.).  This is the reason you can get a "hydraulic lock" in those bottom  cylinders and thus the importance of pulling the prop though before  starting.  

  

 Also oil just dripping out of the cowling, could be the accumulation a  number of small oil leaks.  Hence they flow off the engine from various  places, on to the inside of the cowling, then to the floor.  You can have  leaks from push rod tubes, rocker box covers (18 of them), any of the gaskets of  the various bolt on units.

  

 The best (for me anyway) way catch leaks, is to remove the cowling.   Clean the engine and I mean REALLY CLEAN.  There are many different ways of  doing this however what I do, is mix liquid GUNK with thinner - (1/4 GUNK) and  spray it on the engine with a good sprayer.  Higher pressure will knock of  the heaver crap. You might a stiff narrow brush to get rid of some stains.   Let sit 15 minutes than wash off with water.  (It will not kill your  grass).  Let the engine dry off.  Then run it a good 5 minutes, do a  quick power check, and then shut down.  Then look for leaks.  Check  particularly around the base of the engine where the oil sump attaches.  If  you find oil leaks simply tighten up the nuts first.  Some places you may  need to replace gaskets.  WARNING;  If you find oil leaks at the very  base of the push rod tubes, DO NOT try to replace the "O" rings underneath where  the housing is bolted to the case.  Simply tighten the 2 nuts AND  LET IT BE.

  

 That about it.  Others on this list can add to this I am sure.

  

 Jim "Pappy" Goolsby

  

  

  

  In a message dated 12/30/2015 1:02:55 P.M. Eastern Standard Time,  Andrew.park(at)xtra.co.nz (Andrew.park(at)xtra.co.nz) writes:

  	  Quote: 	
		  -->    Yak-List message posted by: "Yakman"    <Andrew.park(at)xtra.co.nz (Andrew.park(at)xtra.co.nz)>



Morning everyone. Happy new year to you    all.



My 18t appears to have developed an oil leak. I arrived at the    hangar to find oil dripping from the bottom of the cowl, not a big leak but    it's never done this in the 5 years I've owned it. Rather 

than reinventing    the wheel, are there some common areas I should 

look first? Oil pressure    is normal and it certainly doesn't squirt 

out when I start    it.





Read this topic online    here:



http://forums.matronics.com/viewtopic.php?p=451516#451516===============================================

_nbsp;             (And Get Some AWESOME FREE     to find   Gifts       nbsp; List  k you for  p;                        -Matt Dralle,    List  ========================  e  ties  Day  ================================================               - MATRONICS WEB FORUMS  ================================================             - List Contribution Web Site  sp;                             ===================================================

- The Matronics Yak-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Yak-List

_________________
Viperdoc

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