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  #1  
Old 08-13-2008, 07:39 AM
Mike Ice Mike Ice is offline
 
Join Date: Apr 2006
Location: Sedro Wooley, WA
Posts: 147
Default oil filler tube leaks

Hello,

There is a leak at the base of the oil filler tube on my new engine. Is this common? I will attempt to tighten it today. I was just wondering if anyone else has experienced this problem and what is/was the fix?

Another RV-9 took to the air last Sunday. This one is in Alaska. I flew 8 hours yesterday and am still trying to figure out how to land gracefully. Most of the landings so far have been more arrivals but this little airplane flies great.

Mike Ice
Flying RV-9
9 hours
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  #2  
Old 08-13-2008, 07:59 AM
mahlon_r mahlon_r is offline
 
Join Date: Jan 2005
Posts: 1,025
Default

Pretty common leak, especially after a long storage period. The gasket under the tube shrinks a little bit over time, requiring the tube to be re-tightened and re-safety wired
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."
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  #3  
Old 08-13-2008, 08:07 AM
N941WR's Avatar
N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
Posts: 12,887
Default

Mike,

Good to hear another -9 is flying.

Keep working on those landings, they will come. Because of the wing, both three point and wheel landings take precise speed control to master. By the end of your 40 hours, you will wonder what the big deal was. Besides, with that BIG VS and rudder, it is very easy to keep straight.
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RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
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  #4  
Old 08-13-2008, 09:15 AM
Steve Steve is offline
 
Join Date: Jan 2005
Location: Roy, Utah
Posts: 1,144
Default leak

Remove the tube and gasket. Clean the mating surfaces and the gasket. Apply a coating of fuel lube to the gasket. Re-install the tube by hand. My tube is plastic so I lightly snugged it with a wrench just to verify it was seated against the engine case. Safety wire and go.

Still dry after 75 hours,
Steve
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  #5  
Old 08-13-2008, 09:16 AM
rvbuilder2002's Avatar
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
Default

Common problem since the tube is a builder installed part on most engines (they are delivered without the tube installed making it easier to get the engine on the mount, etc.)

One operational cause is over tightening the dip stick. It does not need to be cranked on tight. Just lightly snug will keep it on. If you over tighten, it puts a lot of torque on the tube when removing it. This breaks the seal and you then have a leak.

What I do...
Start with a very clean dipstick tube, engine case, and gasket (you can reuse the old gasket if you can get it cleaned up real well).
Put a super thin coating of high temp RTV on both sides of the gasket (this should be just enough to wet the surface, you don't want a big blob of RTV squeezing out inside your engine).
Install the tube and gasket.
Use a big wrench on the nut portion of the tube to get it snugged up tight. It needs to be good and tight but remember it is made of plastic.
Now for the most important part...Use .041" safety wire to safety the tube. It is very important that you get the safety wire pulled very tight. This is to prevent the tube from being able to rotate even the minutest amount. If the tube ever rotates at all you have another leak because the seal has been broken. If your first try with the wire isn't tight, take it off and try again until the wire is stretched good and tight
Now condition yourself to not over tighten the dipstick (ever notice that it gets even tighter and harder to remove after the engine is hot).

This will usually provide a leak free dipstick tube for a long time.
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Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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  #6  
Old 08-14-2008, 09:03 AM
Mike Ice Mike Ice is offline
 
Join Date: Apr 2006
Location: Sedro Wooley, WA
Posts: 147
Default leaky tube

Many thanks for the great tips. I will try them all or at least one at a time today when I change the oil.

Mike Ice
18.7 hours and still smiling, actually the smile is getting larger.
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  #7  
Old 08-14-2008, 03:11 PM
Stu McCurdy's Avatar
Stu McCurdy Stu McCurdy is offline
 
Join Date: Jan 2005
Location: Round Rock, TX
Posts: 211
Default Oil Filler Tube Leak

If you put REAL gaskets (the orange ones) on your Rocker Box Covers, they come with a Dip Stick orange gasket also. Put that on, hand torque, safety wire and there will be no further problems.
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Stu McCurdy (Falcon)
RV-8, 78TX, Flying
Formation Flying, Inc (FFI)
Falcon Flight
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  #8  
Old 08-14-2008, 05:43 PM
Dmadd Dmadd is offline
 
Join Date: Jul 2008
Location: Camas, WA
Posts: 481
Default

What Stu Said...
Had same problem, thats how I fixed it... "Real Gaskets"
DM



Quote:
Originally Posted by Stu McCurdy View Post
If you put REAL gaskets (the orange ones) on your Rocker Box Covers, they come with a Dip Stick orange gasket also. Put that on, hand torque, safety wire and there will be no further problems.
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  #9  
Old 08-15-2008, 08:49 AM
Mike Ice Mike Ice is offline
 
Join Date: Apr 2006
Location: Sedro Wooley, WA
Posts: 147
Default Still have a leak

Folks,

I removed the oil tube filler yesterday and found a robber O ring on it. I replaced the O ring with a regular Lycoming gasket and thought that had to be the problem. But no joy. Well that O ring was probably leaking as well because it was "sqiushed" out from being over tightened.

Now I am beginning to think the fitting just above it that has the oil line that goes to the pressure sending unit might be the culprit.

Does anyone have any experience dealing with a leak in this area? Was it the line or the fitting? How did you fix the problem?

It looks like if I have to remove that fitting I will have to remove the engine mount. Does that seem right? Any tips on this will sure be helpful.

Mike Ice

a little over 20 hours and enjoying the process but I will enjoy it a lot more when I can stop this pesky leak.
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  #10  
Old 10-06-2008, 07:10 AM
Mike Ice Mike Ice is offline
 
Join Date: Apr 2006
Location: Sedro Wooley, WA
Posts: 147
Default oil leak found

Finally found the source of the oil leak. I hope.

The high pressure oil bypass gizmo, not the correct term but I can't remember the name, which is located right above the oil filler tube just to the rear of the #3 cylinder was the problem.

The fitting has a spring and a ball bearing in it which can be adjusted to regulate oil pressure in the motor. The fitting had a small crack around the threads and I could not see it until this last time I took it out and replaced the crush gasket under it. Each time I took it out to examine it and replace it the crack got larger when retightening so the leak got worse but finally the crack was also large enough to see.

The oil leaked down from that part and got into the airflow and was then spread around which made it difficult to pin point the source of the leak.

As soon as I can get another part I will install it and hopefully the leak will be history.

Mike Ice
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