REFLECTOR:Oil Leak Detective

[Chris Martin]

Chuck, This is a post I sent last year.

I have been battling some mysterious oil leaks for about 1 year and I am
now appealing to the great assembled, online think tank for some advise.
This is addressed to both the carnard-aviators and the velocity reflector.
 
I am flying a Velocity XL RG with a Lycoming IO-540. My two sons and I
finished it 2 years ago and have since flown 250 hours. It flys great and
we couldn't be happier. The only problem is that it has a tendency to leak
oil into the engine compartment. The amount of oil is not significant,
perhaps 2-3 oz per flight but it is messy. It is not coming from the oil
breather. I have an oil separator that does a beautiful job of separating
out the breather tube. The oil leak manifests itself as a film of oil all
over the engine and prop and after shut down a puddle of 2 oz of oil forms
on the ground under the plane.
 
I've checked everything: rocker covers, case bolts, filter, push rod tubes,
oil return lines, etc. I have replaced a few of the push rod tube seals and
in one case produced some improvement. In a few instances I have removed
(one at a time),a 3/8 inch case bolt, cleaned it with MEK, and replaced it
with permetex aviation sealant on the washers and threads. This also showed
some degree of improvement. My best procedure for searching for leaks is
the following: remove all cowlings and plenums, wash the engine with engine
cleaner and a pressure spray of water, dry the engine with compressed air,
finally, wiping down the engine to remove any trace of oil residue. Now,
with a perfectly clean engine, start up, warm the oil and run the engine at
1800 rpm for 2 minutes, shut down and check for leaks. On these few
occasions I have found some obvious leaks which I repaired. I have also
found some oil on the threads of the case bolts as if the oil is coming
right through the nut and washer and off the end of the exposed threads!
 
After performing this procedure 3 times, I'm worn out and have maybe
reduced the leaks by 30%. Is this normal? Is this typical only for pusher
engines? How many of you have this problem? (Please raise your hands).
Everything else on the plane is normal including engine temps: 390F  CHTin
cruise with a max of 415 F CHT on climb out. I add about 1 qt. of oil per
6.5 hours which seems low given the fact that it leaks 2-3 oz per flight.
One other symptom; if, on landing, I keep the shock cooling to a minimum as
in 20F change per minute as opposed to 45F change per minute (max allowable
is 50F), the problem seems to be reduced.
 
Any advise?
 
 
--- 
--- christophercmartin@earthlink.net
--- EarthLink: It's your Internet.
 




> [Original Message]
> From: Chuck Jensen <cjensen@dts9000.com>
> To: reflector@tvbf.org <reflector@tvbf.org>
> Date: 9/28/2003 9:22:39 AM
> Subject: REFLECTOR:Oil Leak Detective
>
> I've had a chronic, if small, oil leak for the last few dozen hours of op.
> Two mechanics have looked at it and haven't spotted anything.  The leak is
> small, just barely enough to mark the lower cowling and form an occasional
> oil droplet where the lower cowl meets the body.  
>
> I consistently operate at "9" on the dipstick and doesn't seem to be blow
> over.  The leakage is small enough that it doesn't makes any difference in
> oil consumption for the engine.  The general area of the leakage seems to
be
> in the middle, back of the engine, but given the squirrelly air flows, et
> al, it's always a little difficult to say with certainty.  I keep
suspecting
> the oil filter area but that hasn't been productive so far.  Naturally,
the
> suspect area(s) are also the hardest to get to, look at and are the most
> congested.  Background: IO-540.
>
> From time to time, a whitish spray-on material has been mentioned for
> tracking down oil leaks. Can any one expound on the materials, where to
buy,
> how it's used and the pros/cons of different detection techniques?
>
> In checking the web, Tracerline UV/dye system seems to have a lot of buzz,
> but adding anything to the oil, no matter how innocuous that it's alleged
to
> be, always gives pause.  Anyone ever use it?
>
> Chuck Jensen, in East Tennessee looking for a "0" leak engine.
> _______________________________________________
> To change your email address, visit
http://www.tvbf.org/mailman/listinfo/reflector
>
> Visit the gallery!  www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html