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Do I have an oil leak?

tom paul

Active Member
Greetings RV Family.
I am in the middle of my second oil change on my RV7A. Titan XIO360.
I am wondering what normal should look like regarding oil on the engine.
When I took off the bottom cowling, OI saw that many surfaces on the bottom of the engine are slick, and there is a drop here and there. I am attaching some pics.
The engine does seem to use oil. I put in seven, and after a flight it is six. During preflight, I often find it around 5 3/4 so I add a quart or part of one. The engine never stays filled to seven, but seems to stabilize around six or just under, but I never let it get under five and a half. Just wondering if these pics indicate that there is something that I need to address regarding a leak somewhere.
Thanks!
I've never posted pics before. I am doing what someone suggested in the sticky thread and using google photos. They seem to just be links. Please let me know if this worked and you can see them
 

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I can't see the pics since I don't have a google acc't. It's pretty easy to:

After typing your message, click on the paper clip in the top row of icons > new window will appear > click browse > find your file > click open > click upload > go back to the typing window and click on the paper clip again. > click on the downloaded file

I calculate my oil consumption as tach time to go from 6 to 5 qts, in my case about 12-14 hrs.
 
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Nosee

No pics showing after i login to my google account. If pics r on device that u use to post, use the paperclip icon to find, upload pics then exit pic mode.
 
Greetings RV Family.
I am in the middle of my second oil change on my RV7A. Titan XIO360.
I am wondering what normal should look like regarding oil on the engine.
When I took off the bottom cowling, OI saw that many surfaces on the bottom of the engine are slick, and there is a drop here and there. I am attaching some pics.
The engine does seem to use oil. I put in seven, and after a flight it is six. During preflight, I often find it around 5 3/4 so I add a quart or part of one. The engine never stays filled to seven, but seems to stabilize around six or just under, but I never let it get under five and a half. Just wondering if these pics indicate that there is something that I need to address regarding a leak somewhere.
Thanks!
...

This is a common problem, but not normal. There is oil leaking from somewhere, if you have oil outside the engine.

It's not always easy to find the source. If you are lucky, it's one of the 4 oil drainback tubes that need either replacement or tightening.

BTW, I also can't see the pictures - just use the paperclip to upload - much easier, and better for VAF and its future users.
 
I have a Licon IO-360EXP. I would add at 5. I think Lycoming recommends adding at 4. My oil temp seems to go up slightly if I wait 'til 4.
 
Pics added

thanks for the tips on adding images. Done. I am a newbie under the cowling, though I have a bunch of automotive engine experience. I'd love some specific tips on how/where to start solving this.
Thanks and enjoy your Sunday!
 
thanks for the tips on adding images. Done. I am a newbie under the cowling, though I have a bunch of automotive engine experience. I'd love some specific tips on how/where to start solving this.
Thanks and enjoy your Sunday!

I have a similar engine (Titan O-360 instead of IO-360) and some similar leak issues.

The advice I've gotten both here and from the local mech is to get the engine as clean as possible by spraying with some kind of solvent - Avgas works, so does mineral spirits and opinions vary on which to use - and then doing some tests to see where the oil surfaces.

On mine, I've got a couple of minor leaks - one very slight weep at my case halves which is not uncommon, apparently, but not a **** of a lot I can do about it. Have another one, it seems, coming from my prop governor, I think, but I'm still investigating that one. May have a third at the oil drain back lines...I'm in the middle of this process.

Kitplanes had a pretty good article on chasing these down - https://www.kitplanes.com/leaking-lycs/ and it might be a good place to start.
 
Oil will commonly come out of the breather tube during flight whenever you have more than about 6 quarts or so. Stop topping it off and let it get down to 5 or 5.5 quarts before adding more.
 
Thanks Erich!

I will degrease the shiny/drippy parts before putting it back together this time, and see what it looks like after running a bit with 5 quarts or so. What amount should I add initially, considering that there is a new filter to fill?
Also, I am going to add camgurad for the first time, after reading about it a lot lately. Engine has 1240 hours on it.
Thanks!
 
I will degrease the shiny/drippy parts before putting it back together this time, and see what it looks like after running a bit with 5 quarts or so. What amount should I add initially, considering that there is a new filter to fill?
Also, I am going to add camgurad for the first time, after reading about it a lot lately. Engine has 1240 hours on it.
Thanks!

As a general rule, the Lycs will spit out anything above 6 quarts in our installations - how hey spit that out, and how your breather tube is routed will determine if it goes on the belly directly, or blows around the engine compartment before greasing the belly.

Clean it, run it between 5 and 6 quarts, and see what it looks like.

And of course the obvious answer to “do I have an oil leak?” Is “you have a Lycoming - of COURSE you have an oil leak!” Standard old joke…..

Paul
 
Me too

….. been chasing, got some facts/tips for you.

Clean all oil from engine…. I use long hemostats with small rag to reach nooks and crannies.

? Is oil above/within baffles or just below…if just below, quit looking above.

Never run more than six qts, let it get below 5.5 then top off. Excess oil in this case does not end upon engine, but belly of your bird. Lycoming recommends no less than 4 qts I believe.

Check dip stick tube is tight and safety wired so not to loosen.

Check ends of oil lines…are they tight at cooler ends and engine ends. Check steel fittings on cooler and engine if/when applicable.

Airflow in flight does weird things to liquid leaks. It gets on everything and make it difficult to find source. Remove cowl, chock mains, run 1200rpm LEANED TILL ENGINE STUTTERS, RICHEN UP A LITTLE. No chance in over heating unless hot outside. Run engine 30-45 minutes… pull back in hangar and start looking. If you wait, the oil will drip down, making source more difficult to find. I expect oil to be obvious at the source at shut down, not a day later, or even hours later.

If leak is below/behind baffles, check oil cooler, cooler hose ends, mag gaskets, and fuel pump gasket, and oil sump gasket. Look at horizontal surfaces that could catch oil. Do you see drops ? If so look above, likely your source.

For me appears my oil sump gasket is leaking, finding drops on top of my airbox…below front of oil sump.

Lastly…… i used UV dye in oil ( 1 ounce, no harm to engine) and a black light to find mine after trying all other means. Oil does glow under black light, but test, to know yours does for sure…Phillip’s XC Victory is aqua blue under black light. With uv dye from auto parts store bright orange. I don’t believe yours is coming from engine block seam or the cylinder drain back tubes….Good luck
 
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thanks Paul!

It's probably the breather because I do tend to top her up to 7 once in a while. I won't do that anymore.
Speaking of oil leaks, I used to be a lineman in Rochester NY, back in 1986. I was working the night shift when the check-runners would come through in their DC3! Spitting purple fire in the night sky, and dragging their fabric-covered tails around the ramp.
I was responsible for everything from fuel and oil to driving the forklift to load them up. DC 6's as well sometimes, with GM engines from the Rochester plant.

There was a salty old pot-bellied DC3 pilot I remember well:

Me: "will you be needing any oil this evening, sir?"
him: "she-it, go look at the **** airplane! If it ain't drippin, it musta run dry, so yes, I need oil!"
 
My buddies Superior IO-360 Cozy MKIV developed some pretty bad oil leaks at around 700 hours. It’s hard to pinpoint where the leaks originate. It uses updraft cooling and the air blows the oil all over. Since he’s in Florida and I am in Michigan, I wasn’t much help in tracking down the leak. He finally got one of the airport AP’s to come take a look. Turns out that a couple of the pushrod tube seals at the cylinder tops had shrunk so bad you could actually see light from a flashlight where there was no longer any contact. Replacing those seals on all 8 tubes helped diminish the leaking oil greatly, but he still has a small leak or two somewhere else.
 
I have had good luck with mineral spirits and the home depot spray bottle.. soak down the engine with the spray bottle, then before it dries, hit it with a garden hose. It’ll be clean enough to eat off of. Then you can do the engine run to look for the leak. My hangar neighbor had a leak and a little dusting with baby powder helped find it. As for how much to add after an oil change, add 5 and run it to fill the filter, then recheck and top it to where you want it..
 
Not an obvious oil leak

Chasing a small oil leak for a long time with no luck.
The engine did´t run very smooth at 700 rpm and i finally decided to
replace the intake paper gaskets with SDS O-ring kit.
Amazingly the oil leak disappeared and the engine now runs smooth again
at low rpm.
 
SDS O-Ring kit for Intake Tubes.

SDS Aero O-ring Sealed Induction Tube Flanges.
Installed these on O-320 160 HP along with new oil drain hose from each rocker box & new compression clamps. That and Anti-Splat air/oil separator and COMPLETE CRANKCASE VACUUM KIT.
Eliminated 99% of oil seepage.
 
Here is a trick that can save lots of time hunting down oil leaks.

Thoroughly clean engine with mineral spirits using a spray wan with a suction hose in the can of mineral spirits. Then follow up with avgas to get the engine completely dry and clean of all oil

Buy a can of Dr Scholls foot powder spray and spray down suspected areas.
The spray will leave behind a coating of white powder residue.

Run engine for 5 minutes and the oil leak will be easy to spot

Make sure it’s Dr Sholls foot powder spray, and not a cheaper store brand name. Those do not contain enough powder to leave a coating for the oil to soak through.
 
Tom, The amount of oil that I see on your starter would have me checking the front crank seal. Take a paper towel 1/2 sheet and fold into a rope and wrap it around the crank between the flange and the case. Give it a minute, it should come out DRY!!

If that area is dry, then you are very lucky and now you can look elsewhere.
 
Have to agree with the Gas man, I had a leak I chased for 6 months and found it just last week, my main crank seal was turning in the case only seeping a bit onto my alternator occasionally, look with a mirror and turn your prop to find that gremlin !
 
My experience goes with elev666 and gasman. Usually when I see oil on the starter and dripping off the bottom of the carb or fuel servo my attention goes to the front seal. Some will discount that because they can run their finger inside the hub and find it dry, however sometimes it will bypass that and run right down the split in the crankcase. I clean the engine and use dye penetrant devoloper and it works great. Bonefishdave's idea of using spray foot powder is brilliant. It will do the same job is cheap and readily available. I suggest after cleaning. Applying powder or developer to sustpect areas, take it out and do a runup first to check for leaks. If its what I think it is you may have to take it around the patch once to find the leak. Any more than that and it tends to spread all over. Good luck!
 
Didn’t see if it was as a fixed or constant speed. I actually had a very small leak that would leave a drop or two on the starter/alternator and a 1/2 dollar puddle in the aft co-pilot cowling. Nothing around the front crank seal, but removing the prop I had a couple drops.
I thought I was sold a solid crank fixed pitch only engine, come to find out it was hollow and needed the center plug removed for fixed pitch props. Oil was being forced out the front of the crank freeze plug, glad I caught the issue before the oil lubed the prop anymore than it was…..
 
There may be be a slight hint of oil from the exhaust on start up if it is pointed aft other than downward a bit, this is because after shut down, some slight amount of oil can seep past the guides and onto the valve and go out the exhaust on the next start up. Another area to look for when all else has failed, is that there are several instances of the quick drain valve dripping small amounts of oil.

DAR Gary
 
thanks everyone

I will do the cleaning and leak hunting when I can, likely after the holidays.
In the meantime, the oil has been drained, the filter still in place, and it is sitting in a freezing hangar. Is that OK? To sit with no oil in the cold?
If it does turn out to be a leaking front crank seal, what does it take to fix that? Is it a "don't fly until it's fixed" type of thing, or is it not likely to progress in severity? It sounds like a major disassembly with prop removal to get to the crank seal, is it not?
 
Slight leaks from crank seal are fairly common and there is no need to fix before further flight. Yes, a bit of a pain to fix, more so with some props than others. Personally I dread removing my Whirlwind prop due to the tight spacing of the prop nuts and difficulty in safety wiring them when re installation. I am waiting til I do a prop overhaul before fixing the slight leak from mine. Replacing the crank seal can be done with some effort and patience, but be sure to do a search for posts on that process and read up on it first if you really want to do this. I’ll bet there are some you tube videos showing the process as well.
 
I will do the cleaning and leak hunting when I can, likely after the holidays.
In the meantime, the oil has been drained, the filter still in place, and it is sitting in a freezing hangar. Is that OK? To sit with no oil in the cold?
If it does turn out to be a leaking front crank seal, what does it take to fix that? Is it a "don't fly until it's fixed" type of thing, or is it not likely to progress in severity? It sounds like a major disassembly with prop removal to get to the crank seal, is it not?

A couple of things to add . . . (not oil). There is no reason to accept that a lycoming can not be dry, i.e. no oil leaks. It is a personal choice. A good A&P told me to look for the highest drip and seal things above it, then work your way down. I did and now only the oil fill tube is on the list after 200 hrs. Others notes on cleaning, +1.

You should know that AeroShell will glow with UV light. Amazon has one, and don't recall the nm of the wavelength(edit: 395nm). DO NOT use this in a hotel room!!! Oil return hoses need constant force clamps. Posts are on VAF somewhere. Use Google to site-search VAF.

Happy hunting!
 
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Crank seal

If a crank seal leaks, generally you find oil around that area of the TOP cowl. It is slung UP, by the spinning. A seal that rotates has lost it glue joint, crank seals are “glued” in Pilobond just one of several approved adhesives , a 3m brand too, forget the full name. I recommend getting an A&P to give it a look before you do the work to replace. Not done right, could cause big issues…. Losing all oil in flight. Not to scare ya, but fact.
 
Follow Paul's instructions here:

https://www.kitplanes.com/leaking-lycs/

I went through this entire process...my engine was as bad or worse than yours and this is where I found the leaks...

  • Leaking thru bolt on middle main
  • Cylinder packing on #1
  • Crank seal (only slightly)
  • Drainback tubes replaced with new and changed worm clamps for spring clamps
  • Mechanical Fuel pump was seeping oil from perimeter of diaphram

The thru bolt was the biggest leaker, and the most involved fix with SI1290, but now my engine and belly is bone dry.

One thing I'll add that others have not...20W-50XC is also UV reflective, so a UV flashlight in the darker worked great. New oil reflects UV the best.
 
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