Discharge from breather hose

[turbobullet]

Just noticed this after the last flight, after only 45 minutes in the air. It's a yellow discharge from the breather hose. Does not seem to have an odor. This is on a 1987 M20K 252 just out of annual after many years of neglect, flying regularly now. No other noticeable issues. Any ideas?

[takair]

Moisture mixed with oil.  How long was the flight?  May have had some condensation build up and freshly topped oil mixing.  Good excuse to go fly another hour....

[EricJ]

Could be an STD.   Has it been parked near other questionable airplanes?

Or keep an eye on the oil.   Flying it should get the moisture out, but if it stays goobery change it again. 

 

 

Edited April 13, 2021 by EricJ

[takair]

Oh...one more thought....check the dipstick....my guess is it does not look like that in the sump.  If it does, change the oil again, as Eric suggested.  What is your oil temp running at?

[A64Pilot]

3 minutes ago, takair said:

Moisture mixed with oil.  How long was the flight?  May have had some condensation build up and freshly topped oil mixing.  Good excuse to go fly another hour....

This, either short flight or possibly high altitudes where it was really cold

[turbobullet]

2 hours ago, EricJ said:

Could be an STD.   Has it been parked near other questionable airplanes?

Or keep an eye on the oil.   Flying it should get the moisture out, but if it stays goobery change it again. 

 

 

Yes, we were parked near other airplanes, but I don't think it was STD because we were socially distancing...we're the third one at the end.

[geoffb]

I'm new to the Continental, but mine does the same.  Seems to be emulsified crap collecting in the separator and heading out the vent.  Was worried about it until I changed the oil and no trace of moisture in the sump.  So, I guess it's normal

My Lycoming didn't have a separator, so it had a clear discharge.....

[rgpilot]

Relief tube?

[FlyingDude]

On 4/14/2021 at 12:29 PM, geoffb said:

no trace of moisture in the sump

How do you look for moisture? What's the test method? Thanks

[A64Pilot]

On 4/16/2021 at 7:59 AM, FlyingDude said:

How do you look for moisture? What's the test method? Thanks

Oil and fuel for that matter will always have some water in it, called entrained I think.

‘An excess of water in oil will emulsify in the oil and turn it milky, just a little water will have milky strands in the oil.

‘I’ve never seen crankcase oil get that much water in it except for a liquid cooled engine with a blown head gasket or a farm tractor left out in the rain or something, so it just shouldn’t be possible for an air cooled airplane motor to get excess water in the crankcase to the point that it turns oil milky.

The crankcase breather tube is metal, and if it’s cool enough from cold weather or hasn’t heated from a short flight, it’s possible for it to condensate moisture from combustion , then that little bit of oil and water can mix and turn milky.

‘Oil and water don’t mix normally, but water can be emulsified in oil from being hot or excessively agitated, like a crankshaft beating it into a mixed state, so hot oil mist and hot moisture can come out of the breather tube and condensate together into an emulsification.

‘The white milky looking coolant you’ll see in a machine shop is often a water / oil emulsification. 

 

The test method is to pull the dipstick and look to see if it looks like you have a milkshake in your crankcase, but I don’t think you will ever see that in an airplane

Edited April 17, 2021 by A64Pilot

[ArtVandelay]

But that looks like a lot of water, more than just the result of combustion. I live in Florida, high humidity and have never seen that.

[A64Pilot]

Oh,and silicone hose and petroleum products like oil don’t mix well.

Unkess of course they are Viton lined, not real common, but Viton is pretty much impervious to just about anything.

[A64Pilot]

4 minutes ago, ArtVandelay said:

But that looks like a lot of water, more than just the result of combustion. I live in Florida, high humidity and have never seen that.

I’m theorizing that’s it’s just a tiny bit of water, emulsified with just a tiny bit of oil. I’ve seen it, but not frequently, usually when it’s cold and you go fly just enough to change oil etc.

[takair]

1 hour ago, A64Pilot said:

The test method is to pull the dipstick and look to see if it looks like you have a milkshake in your crankcase, but I don’t think you will ever see that in an airplane

I recently saw this in a Cessna.  All of the oil looked like this.  Less than 30 hours on the oil.  I suspect it is from short, low power flights.  Aircraft is hangared, can’t fully explain it.

[A64Pilot]

Short, low power flights, and cold weather maybe. Some aircraft like my little C-140 you just can’t get the oil up to temp in cold weather so all you can do is shorten the change interval. All my airplane flying has been in warm weather, I don’t do icing for example. Sure I’ve been as far North as the Article Ocean, but in July.

‘I tell people that I’m allergic to cold and equate cold to pain, so I just don’t have airplane cold weather experience.

‘I’ve flown in cold weather, just not piston airplanes

‘What kind of Cessna?

[Will.iam]

1 hour ago, takair said:

I recently saw this in a Cessna.  All of the oil looked like this.  Less than 30 hours on the oil.  I suspect it is from short, low power flights.  Aircraft is hangared, can’t fully explain it.

Last time i saw oil like that was from my boat motor oil change that had a water gasket leak that allowed water into the crankcase. 

[takair]

3 hours ago, A64Pilot said:

What kind of Cessna?

177

[M016576]

8 hours ago, takair said:

I recently saw this in a Cessna.  All of the oil looked like this.  Less than 30 hours on the oil.  I suspect it is from short, low power flights.  Aircraft is hangared, can’t fully explain it.

Oh man... that’s bad...

my 6th sense predicts that Cessna will need a new cam soon.  Maybe a new crank too.

[takair]

4 hours ago, M016576 said:

Oh man... that’s bad...

my 6th sense predicts that Cessna will need a new cam soon.  Maybe a new crank too.

On the watch list. Filter was clean. 

[PT20J]

There was some discussion on Beechtalk recently. I’ve never seen it on a Lycoming. Is it more common on Continentals?

Skip

[LANCECASPER]

Bad batch of oil showing up in different airplanes?

[A64Pilot]

1 hour ago, LANCECASPER said:

Bad batch of oil showing up in different airplanes?

No, that’s water emulsified in the oil. Can only come from moisture of fuel being burnt, so it’s not as much water as it may look like.

‘But I’ve never seen it in an airplane

[Guest]

Continental oil vernatherm valves are set to a lower temperature than the ones in Lycoming engines. Engines not flown long enough or hot enough make this type of paste often found on the oil cap and the crankcase breather.

Clarence

[buddy]

After each flight I pull the dip stick out a few inches and leave it out for about 15 min. allowing the condensation to escape.

[Mufflerbearing]

22 hours ago, M20Doc said:

Continental oil vernatherm valves are set to a lower temperature than the ones in Lycoming engines. Engines not flown long enough or hot enough make this type of paste often found on the oil cap and the crankcase breather.

Clarence

This!

I find that running all winter long, that there is condensation at the breather and at the oil cap.  The oil looks great as the flights I take are long distance which removes the water, but when everything is hot and then cools, it pulls in all of this moisture. 

8 hours ago, buddy said:

After each flight I pull the dip stick out a few inches and leave it out for about 15 min. allowing the condensation to escape.

I do this as well and it makes a ton of difference.