Sniffle Valve - Oil Drip

[885EW]

All,

Been about a week or so since I flew my Mooney (M20S w/IO-550G) and noticed a few oil drops coming out of the sniffle valve onto the nose gear assembly and ultimately the hangar floor. 

Is this cause of concern? Haven't seen oil come out of this valve since purchasing ~70 hours ago. The normal oil blow out from the breather line on the left side of the nose gear doors I see; but this is the first from this valve. My mechanic says it's fine and normal ops for it to drip at times; but I thought it would be more of a fuel or fuel/oil mixture viscosity. Oil change next week where we will take a look once cowling is off for other potential causes, but thoughts or guidance appreciated as I plan on flying this weekend.

Thanks!

 

 

 

 

Edited May 1 by 885EW

[MikeOH]

Are you sure it is actually coming from the sniffle valve, vs just oil dripping OFF it?  I.e., another actual source of the oil.

[201Steve]

Yeah if u haven’t decowled it at minimum, no way to know where it’s. Coming from it gets blown around everywhere. Snifffle valve comes off intake. Would be highly unlikely unless somehow oil getting through the intake valve guide

[PT20J]

Only fuel should drain out the sniffle -- it's purpose is to drain any fuel that accumulates in the intake manifold from over priming or from fuel percolating out of the injector system after a hot shutdown.

Someone recently reported that the fuel pump drain was connected to the sniffle drain line on their airplane. The fuel pump drain is located between the diaphragms and will leak fuel or oil depending on which diaphragm fails.

At any rate, oil from the sniffle line is not normal and warrants further investigation. 

[A64Pilot]

IF there is oil in the intake, she will smoke on engine start, look for that.

[Yetti]

It's not coming from inside the sniffle valve.  Otherwise it would be a drip at the end of the fuel output drain.     This is coming from the hose up above. and draining down the outside of the hose.     Someone might have missed the filler when filling it with oil.

[Phil EF]

If you borescope your cylinders and find oil pooling in the bottom, it has an easy path through the intake valve and tube to the sniffle valve. 
Very common on the IO550C.

[885EW]

Thanks for the replies everyone! Quick (late delayed update...); quick drain valve and oil pan o rings were a bit worn causing a small drip of oil to eventually make its way down to the exit port where the sniffle valve is. New o rings and re secured during recent oil change, and clean bottom cowling and nose gear ensues. Thanks all for the feedback, as always! Safe flying!

[M20F]

Aviation oil turns white like chalk (phosphorus) under a black light.  
 
https://a.co/d/gAUJY28

I find this and a sleeping bag useful.  Wear the glasses.

I generally just look first and if it looks like a Jackson Pollack painting I hose it down with mineral spirits.  For the most part you can generally figure it out without cleaning.  

[M20F]

Also this time of year a lot of planes get the sniffles.  I drop 2-3 Zyrtec in the oil and fuel tanks.  It’s like MMO but fixes the sniffles.  

[Pinecone]

6 hours ago, M20F said:

Aviation oil turns white like chalk (phosphorus) under a black light.  
 

Even better is to add a small amount of UV dye.