Oil quick drain, delayed leak. Fixed it! (I think.)

Shepherd

Shepherd

Final Approach
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Shepherd
Hello,
I have a C-85-8 with an oil quick drain. I've never owned a plane with a quick drain.
I did an oil change, hot oil, send some out for testing, yada, yada, put everything back together.
Four quarts of Aeroshell back in, no leaks.
Taxi around until the oil temp is 140 degrees, no leaks.
Three days later, pre-flight, fly for 2 hours. Eight landings and take-offs. No leaks.
Refuel plane, Put the plane away. No leaks.
Putz around the hanger for 2 hours, no leaks. Go home.
Today I go into the hanger and there is oil directly under the quick drain. Not a lot, the dipstick still reads 4 qts (ish).
Is this normal? Why would this happen? What do I do next?
 
Shepherd said:
Hello,
I have a C-85-8 with an oil quick drain. I've never owned a plane with a quick drain.
I did an oil change, hot oil, send some out for testing, yada, yada, put everything back together.
Four quarts of Aeroshell back in, no leaks.
Taxi around until the oil temp is 140 degrees, no leaks.
Three days later, pre-flight, fly for 2 hours. Eight landings and take-offs. No leaks.
Refuel plane, Put the plane away. No leaks.
Putz around the hanger for 2 hours, no leaks. Go home.
Today I go into the hanger and there is oil directly under the quick drain. Not a lot, the dipstick still reads 4 qts (ish).
Is this normal? Why would this happen? What do I do next?
Click to expand...
Give plane away. It's the only way to be sure. Maybe some grit/grime isn't letting it completely seal up.

Is it at the base of it, or at the end of it?
 
Either crud in the valve, or a bad o-ring, or something is sticky and the spring isn't holding it fully closed.
 
Daleandee said:
Or a friend is having some fun at your expense ... :fingerwag:
Click to expand...
I wish.
I just can't figure out why it would leak hours after being flown. Like I said, I was working on the plane for at least a couple hours after I flew it, and there was no leak while I was there.
 
Spray with solvent to clean it in the drain hole and the outer threads. Then come back much later to see where it’s coming from. Should be easy to see the source if there is no swirling wind from flying and no engine vibration.
 
I have always felt like clamping a cap on my quick drain but haven't.
I would get a new one if your sure it is coming from the quick drain.
 
Back over to the hanger today, to find more oil in the drip pan. About a tablespoon full.
I bit the bullet and pulled the upper and lower cowlings off, just to get more light in there.
Crawl under and stick my head up close enough so I can actually focus on it. I realize the safety wire is wrong. It's pulling in the "loosen" direction.
I cut the safety wire, torque it down, put new safety wire on in the proper direction, torque seal it, and put the plane back together.
I taxied it until it reached operating temperature and put it away. I'll go back in the morning and check the drip pan.
 
Quick-drain valves don't last forever. They have a rubber seal up inside them, in contact with hot oil and all the corrosive stuff that gets past the rings, and they get tired. So sometimes they start leaking.

They're also down at the bottom of the sump where garbage accumulates, chunks of carbon and bits of metal, and that stuff can foul the seating of that seal.

They're just a big version of the quick-drains in your fuel tanks. Same problems: chemical attack and fouling by debris.
 
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