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1 Million Gallons of Oil on m'Belly!

bkervaski

Hellloooooooo!
Testing
Fun times!

On Friday I went out to do my BFR and when I landed there was about a million gallons of oil on the belly of the airplane.

Took the cowling off, cleaned it all up.

Checked the oil, in reality only lost about 1/3qt.

The oil seemed to be collected around the oil cooler (right side bottom firewall on the 14), there was no signs of oil on the engine or near any of the connectors.

I couldn't find any leaks in the oil cooler. I took it off, pressure tested it (using only the "hold and blow" method and some soapy water). There were no signs of weeping near the elbows. No signs the oil cooler was the problem.

On the 14, the engine vent is pointing towards the oil cooler, dumping out over the exhaust.

The running theory at the field is that the vent line was clogged and came free dumping oil.

There was no indication in flight, no pressure drop or anything odd feeling/sounding.

My plan is to, while leaving the cowling off, taxi and run-ups to get the oil warm and see if any leaks show up.

Any suggestions or ideas? Thanks for any advice!

Oh .. and 1/3qt goes a LONG way :D
 
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Just went thru the same. Check the hose coming off the crankcase vent. Mine was fine for 270 hours. Somehow it cracked just aft of the clamp and was hidden at the bottom. Not until I reseated 2 weeping oil fittings and did some ?repair? work on my oil Cooler did I look at the hose. Mine is blue silicon. Replaced with auto hose as a temp fix and now have no weeps or leaks. New hose on order from ACS.
 
Bill---you may have some 'extra' blowby that might require and oil separator. Some do, some dont.

Tom
 
It sounds like this an issue of sudden excess oil consumption and less about where the oil is going, especially if you can connect the dots that the oil is coming from the breather outlet. Is this qty of oil consumption new?

If yes, and is likely coming from the breather outlet, I would recommend doing a compression check. A broken ring, causing increased blow by would be my thought. This assumes that this level of oil consumption is new and appeared suddenly.

Larry
 
Is this qty of excess oil consumption new?

Yes, this is all with one flight and all of the oil was on the bottom of the airplane. My engine only burns about 1/4qt every 5 hours of flight at 62 hours.
 
you may have some 'extra' blowby that might require and oil separator. Some do, some dont

Makes sense, but this is all from one flight ... an event of some kind happened to trigger it. There has been no excessive oil from the breather tube (unless it has been clogged and just all released at once) and the engine has been dry with no issues.
 
The running theory at the field is that the vent line was clogged and came free dumping oil.

That type of event would not increase oil discharge and if anything would reduce it. The event of finally blowing off the blockage would not involve any additional oil discharge and the engine would be discharging less oil while blocked/restricted. Unless, of course, the pressure blow out something else like a front seal, creating a true leak.

Larry
 
That type of event would not increase oil discharge and if anything would reduce it. The event of finally blowing off the blockage would not involve any additional oil discharge and the engine would be discharging less oil while blocked/restricted.

Great info! Keep it coming :D Thanks guys!
 
BFR acro?

My latest BFR had some relatively unusual attitude recovery in it (especially in a Warrior) including an instructor induced light negative g moment designed to confuse me under the hood. It corrosion proofed the belly of the airplane as you described. And chance your event was maneuver related?
 
How did the flight review go? Did you do any zero or negative G maneuvers? I was quite surprised on how much oil dumped on my belly through the crank case vent the first time I slow rolled. Then I installed the inverted oil system...
 
The oil seemed to be collected around the oil cooler (right side bottom firewall on the 14), there was no signs of oil on the engine or near any of the connectors.

Just as a clarification, do you mean on the right side of the belly or within the engine compartment?

The oil film on my belly is straight down the middle which one would expect. If yours start in the middle and migrates to the right, then might have happened during a yawed maneuver or something like that. If it starts from the right side from the cowl line, then more investigation is warranted as I don’t see how the oil from the breather hose could get that far to the right..

Was the belly completely clean prior to this flight? If so, the theory of clogged breather hose may hold more water but then again, if it was clogged that oil could not come out and collect in the hose, then one would have thought this may cause some other issues like blowing the front seal.

Just a note that if you or others are using silicon type hose (I am using it also) you will need to get the type that is approved for oil and not radiator which is much more common. The radiator type hose will not last and will deteriorate from inside quick.

Check to see any sign of oil on your exhaust. The breather hose is routed to the top of the exhaust so hopefully much of it is burnt rather than going on the belly

BTW, a 1/4 qt every 5 hours is awesome, this is about a quart for every 20 hours which is rather unusual for this engine. I believe I burn a Qt every 7 or so but my measurement is still a bit premature.
 
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Yes, this is all with one flight and all of the oil was on the bottom of the airplane. My engine only burns about 1/4qt every 5 hours of flight at 62 hours.

A sudden increase indicates a change and requires investigation. Assuming you were not doing aerobatics during your BFR and no leaks can be identified, most likely scenario is a broken ring. A quick compression test will confirm or exclude that. Also, confirm that you did not add oil before that flight. Overfilling can cause this due to cavitation from the crank.

Larry
 
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How did the flight review go? Did you do any zero or negative G maneuvers?

It was a fairly benign flight ... some airspace work, slow flight, just one stall, etc. Nothing crazy or any turns that exceeded 45 degrees. I would say a very normal flight.

a 1/4qt every 5 hours is awesome

I add about 1/4qt every 3-4 flights, average flight 60-90 minutes. That's the extent of my tracking, I haven't been keeping a detailed oil log as it hasn't seemed necessary.

Assuming you were not doing aerobatics during your BFR and no leaks can be identified, most likely scenario is a broken ring. A quick compression test will confirm or exclude that.

I don't know the procedure for checking compression, I'll have to get with one of the field mechanics for this, but it sounds prudent. Do you think it would be okay to taxi with runups to verify it's not the hose or should I go straight to the compression check before turning it over? Again, there was no loss of power in flight, it's a beast.
 
It was a fairly benign flight ... some airspace work, slow flight, just one stall, etc. Nothing crazy or any turns that exceeded 45 degrees. I would say a very normal flight.



I add about 1/4qt every 3-4 flights, average flight 60-90 minutes. That's the extent of my tracking, I haven't been keeping a detailed oil log as it hasn't seemed necessary.



I don't know the procedure for checking compression, I'll have to get with one of the field mechanics for this, but it sounds prudent. Do you think it would be okay to taxi with runups to verify it's not the hose or should I go straight to the compression check before turning it over? Again, there was no loss of power in flight, it's a beast.

Should be no issue and would be a good idea to identify any possible leaks before addressing blowby. Overhaul shops often find cracked rings that have run that way for hundreds or thousands of hours.

You can buy a compression tester from spruce for under $100. Only requires an air compressor and spark plug socket to use it. Good info on this site for proper procedure.

Larry
 
A buddy once had an oil cooler that developed a small pin hole in one of the fin welds. Oil was collecting in what we thought was a totallly unrelated area in the engine compartment. When oil was hot & engine reved up it would send a very fine stream of oil out, but when engine shut down there was virtually no evidence on the cooler of a leak. We finally caught it by seeing a sun light reflection while running the engine un cowled & after wasting a number of hours checking everything else associated with the engine.
 
A buddy once had an oil cooler that developed a small pin hole in one of the fin welds.

This or a failed hose seem the likely culprits after all the responses ... hoping it's not an engine issue.

Thanks all, keep the advice coming! Very informative.
 
Ahh.. this looks easy.. I just ordered the ATS tester kit

Very easy and you will need to do it at each annual as a minimum so good time to learn and practice. If you lose compression, you can listen in the exhaust or oil fill tube to see if it is your exhaust valve, ring or otherwise as where the air is escaping.

Hope a broken ring is not your case and some other minor issues.
 
I had the same issue and found it to be a cut in the valve cover gasket in the middle of the gasket where the bottom screw goes in. It was split down the middle of the length of the gasket through the screw hole. About 1/4 inch on either side of the screw, dumped what looked like a a ton of oil just like yours on one short flight. Didn't really end up being that much oil but looked bad on the belly, all brand new crystal clear oil too. Changed gaskets hasn't been an issue since that was about 25 hrs ago.

Totally scared the **** out of me but it probably wasn't even a pint of oil loooked like 2 quarts on the belly though.
Can't post pics but could email it to you: the pics of gasket and the pics of the bellly.
 
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The running theory at the field is that the vent line was clogged and came free dumping oil.
I had a breather line clogged once (ice inside the end). It killed the motor when I throttled up to taxi and blew the front seal when I restarted it. I agree that a clogged breather line wouldn't cause more oil to exit the breather.
 
helps to have a knowledgeable person

Walk you thru your first compression test. it sounds stupid simple, but there are some subtleties involved that can be confusing the first time around.

also having a second pair of hands to hold the prop during the test can really help.
 
...also having a second pair of hands to hold the prop during the test can really help.

Yep. I have two airport friends who had different compression tests get away from them. One got a broken arm, one got his head stitched up.

Be careful. Respect that prop!
 
If compression test is done and there is indeed lower compression in a cylinder I suppose that means it's time to pull that cylinder??? If it is a ring, is it just a matter of replacing that ring and putting it all back together or is there more to it? My reason for asking is this. I just did a compression check a few days ago for my annual. Last year and this year, the number 2 cylinder is just at the bottom of acceptable but not as good as the other three... and just like the OP, I have noticed more oil on the belly than usual.

DanH. Thanks for the link to your compression check article. Excellent education.
 
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Walk you thru your first compression test. it sounds stupid simple, but there are some subtleties involved that can be confusing the first time around.

also having a second pair of hands to hold the prop during the test can really help.

And for safety sake DO NOT GET IN THE SWING RADIUS during the test.
 
If compression test is done and there is indeed lower compression in a cylinder I suppose that means it's time to pull that cylinder??? If it is a ring, is it just a matter of replacing that ring and putting it all back together or is there more to it? My reason for asking is this. I just did a compression check a few days ago for my annual. Last year and this year, the number 2 cylinder is just at the bottom of acceptable but not as good as the other three... and just like the OP, I have noticed more oil on the belly than usual.

DanH. Thanks for the link to your compression check article. Excellent education.

First, low compression is not always a broken ring. Often a ring gets stuck from carbon and time and treatment will free it. I suggested a cracked ring in this post due to the sudden onset of specific symptoms. I would not necessarily suggest it if someone did a compression check and found low readings. You first need to determine where the excess air is going during the compression test - Sump, carb/intake, or exhaust.

To replace a ring, the cylinder is pulled and honed. Then reassembled with the new full ring set. You can buy and modify an automotive ring compressor at a pretty low cost. Will also need ring spreaders (cheap) and special wrenche to remove the cylinder bolts.

Larry
 
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Might check the valve cover gaskets for leaking. Sounds like what happened with #4 on my 0-360
 
Is there any benefit to direct compression baselining? The single recording gauge on one cylinder while the others are sparkplugs removed, powered by the starter.

Measures the entire stroke, not just TDC.

Will a ring issue show up more clearly than a differential test at TDC?
 
My numbers for #1-3-4 were 76 or better over 80. #2 was 65/80. My local FBO friend helped me, (A&P). Although he didn't get down and put an ear to the exhaust etc, said he did say he didn't hear any hissing/leaking. As far as the increased oil on the bottom... I never noticed when it actually started. I've just noticed more than the first several years it's been flying recently an increase in oil. I can't say it was a sudden increase... I just don't know. Also I've been watching the oil levels closely and it doesn't seem to need anymore that usual. My usual is maybe a third to half quart in maybe in 10 hours.
 
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Is there any benefit to direct compression baselining? The single recording gauge on one cylinder while the others are sparkplugs removed, powered by the starter.

Measures the entire stroke, not just TDC.

Will a ring issue show up more clearly than a differential test at TDC?

I am a believer that traditional compression tests are generally more valuable than leak down tests (what they call compression tests in the avaiation world). However, there is a place for leak down tests. The combination of both provides the greatest diagnostic benefit.

I think both tests should show a cracked ring. A cracked ring can be a bit tough to catch, as two rings are used and one cracked ring won't change the compression as much as most would expect.

Larry
 
My numbers for #1-3-4 were 76 or better over 80. #2 was 65/80. My local FBO friend helped me, (A&P). Although he didn't get down and put an ear to the exhaust etc, said he did say he didn't hear any hissing/leaking.

Darn, right in the marginal range.

There is definitely some hissing/leaking, even with the 76 psi cylinders; that's why they were not 80/80. The question is where and how much.

Four ways for air to escape:

1. Ring leakage
2. Valve seat leakage
3. Spark plug seat leakage
4. Cracked head

The rings always leak a little unless submerged in oil, so you should expect some crankcase hiss. I try to ignore it, instead checking the other three items first. They are fairly critical, while ring leakage is not.

Opinions vary, but I think the best way to check valve leakage is to drop the pipes, intake and exhaust. That puts your ear right there at the open ports. You may be able to feel blowing air with your hand. You can even slap a sealed cover plate on the port. It's not hard to fabricate. If the leakdown value jumps up, well, there you go....a sure diagnosis. Intake valve leakage isn't good, but it's not nearly as critical as exhaust valve leakage. If the exhaust can't sit in good contact on its seat, it will overheat and melt eventually.

Valve.JPG


Plug seat problems are best found with a bottle of Mr. Bubble.

Don't discount a cracked head. The worst ones leave black oil tracks on the outside of the head, so a visual inspection is a good start. Peer between every fin, in particular the crown and cylinder thread areas. If suspect, bring out Mr. Bubble again.

This is an O-200 cylinder. With it pulled and on the bench, it's easy to seal the base with a plate and a sheet of rubber, and do all kinds of checks. Here the problem was pretty obvious (see the gooey black oil tracks?), but I wanted to see how evident the hiss might be, and I already had the base plate from my A-65 days.

Cylinder%20Testing.jpg


Cracked%20Cylinder.jpg


If process of elimination doesn't net a culprit, it is a ring problem. Lycoming and Continental have very different ideas about static vs dynamic ring seal. Read the referenced service information.
 
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Thanks for your response Dan! To make sure I understand, those black streaks on that cylinder are without fail a sign of some sort of cracking of the cylinder???
 
Thanks for your response Dan! To make sure I understand, those black streaks on that cylinder are without fail a sign of some sort of cracking of the cylinder???

Yes, although to be the cause of your year-old leakdown result, they would probably be more than a streak.

The location in the above photo says the crack is at threaded connection which ties the steel cylinder to the aluminum head.
 
Your expert advice is always appreciated! Thanks Dan! When I get back from Sun and Fun, (driving this year), I'm going to have another look at my number 2 cylinder!
 
Just curious if the source of oil leak was found?

Yep! One of those little blue aluminum elbows had a hairline crack. Only discovered after replacing the oil cooler and one of the hoses, it was the only thing left.

Note that the oil cooler manufacturer wants us to use steel fittings, although I put new Vans recommended fittings back in place.

(I didn't want to de-rail the thread, was turning into some informative stuff)
 
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Yep! One of those little blue aluminum elbows had a hairline crack. Only discovered after replacing the oil cooler and one of the hoses, it was the only thing left.

Note that the oil cooler manufacturer wants us to use steel fittings, although I put new Vans recommended fittings back in place.

Curiosity question...was the cracked elbow a real AN fitting? If not, I missed it on the TC call.
 
Curiosity question...was the cracked elbow a real AN fitting? If not, I missed it on the TC call.

They are blue anodized AN822-8D fittings supplied by Vans. The manufacturer of the oil cooler said we should be using steel fittings. I re-installed new AN822-8Ds per the manual, did not install steel fittings.

In my rush to reply "hairline crack" may have been a hasty choice of words ... I guess it could have just as easily been damaged threads on the compression side but I did not see a thing wrong with this fitting but you can see it leaking when the engine is running ... sure enough, replacing it fixed the problem.

It took two people and three engine runs to find it, they had to get real close and personal as the oil was a tiny jet like spray, got everywhere .. again

Edit: But .. this was after just over 60 hours of flight so whatever happened to it happened suddenly, within 1 flight. I don't know how one of these could fail, has not moved since installed.
 
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Just an example . .

I don't know how one of these could fail, has not moved since installed.

I still don't know exactly where this failure was . . . cooler boss, threads, fitting, hose

Regardless, here is a possible failure example . . . if the steel fitting was installed with 567 sealant and was tight, the NPT creates hoop stresses the thread hub. Oil pressure is not steady, it pulses due to volumetric variance as the pump rotates. This pressure and ripple can add to the tension stresses created by installation. If the NPT installation pushed the boss to near the stress limit, the cycling could have completed the fracture. It would have presented itself suddenly.
 
....steel vs. aluminum...
....manufacture vs. Vans....
I?m surprise no Vans rep has chimed in on the science of all this. How about some clarity on why Vans would go with aluminum fittings against recommended application by the manufacturer.
Should I swap out to steel?

R
 
Steel

Just looked this up on the Pacific Oil Cooler site. Articles - Common Oil Cooler Woes > They advise to use steel, with thread lubricant. Only use aluminum as a last resort. (Maybe AOG?)
I installed per their advice. But mine is a 7 - different? Have also heard same advice from more than one A&P.
 
From what I understood to be the reason for the steel, is that the aluminum fitting if not used properly can mess up the thread. A good lubricant is required for a successful installation.
 
Use lube for ANY installation . .

From what I understood to be the reason for the steel, is that the aluminum fitting if not used properly can mess up the thread. A good lubricant is required for a successful installation.

This topic has been beaten down several times before. As a single data point, I had to remove an aluminum fitting from my oil cooler after it was installed and sat for a few months. It came out without pulling any threads.

BUT It will gall if installed by hand dry though, so it truly is sensitive. I did that too, just lightly threaded it in and got stiff quickly, removed , chased the threads (lightly) and noted never to do that again.

Bill, where exactly was your crack?? The cause could be the fittings in the boss, but also a hose without adequate room to allow the engine to rock generously can break something too.
 
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Bill, where exactly was your crack??

I really couldn't tell you ... at the time I didn't care much about digging that deep ... once replaced, problem solved, moved on.

Was obvious though, a single tiny stream of spraying oil, that whole area was soaked in a matter of just a minute or two at idle.

I'm concluding it was the fitting because everything else was replaced first, i.e., oil cooler and the suspect hose.
 
I had the same issue with an AN fitting going into my remote oil filter mount. For months I tried to get the leak solved and never could do it. Time and time again I?d pull the fittings out and attempt to reseal the threads.

I eventually discovered that the aluminum fitting itself had a micro-crack inside the fitting. Months of frustration ended by simply buying a new fitting and sticking it in the hole.

It came in as a new fitting but it had a crack. It wasn?t visible to the eye but the oil had no problem finding it.
 
Bill, Phil, those cracked fittings...are you sure they were genuine MIL-spec AN? Look-alikes are called "AN" in every hotrod catalog, and often have the part number, but it doesn't mean they meet the spec. The look-alikes have also been known to sneak into inventory at legit aircraft vendors; ignore the source and check the fitting.
 
This specific fitting was supplied by Air Wolf with my remote filter setup. There?s a chance they supplied a look-alike, but they do sell certified products so it?s doubtful.

At the end of the day, I can tell you how I got it, and that I got it from a reputable supplier.....But their source supplier is not 100% known.
 
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