Oil breather drip

[Flymu2]

My oil breather drips oil on the nose gear door. Any way to prevent/minimize the drip and/or the staining on the door?

[aaronk25]

Move the exhaust end of the breather out a bit further. Or put in a airwolf oil seperator at a cost of about $900 installed including labor.

Or the best answer would be to wipe it off now and then....

[Jeff_S]

You could install an air/oil separator, which may help a little bit. I had one on my J which worked like a charm, but I have heard mixed reactions to putting one on Continental, as well as which brand to use. The Air Wolf seems to get better reviews but is much more expensive than the M20 model.

 

Other than that, I just keep a rag devoted to wiping this off after each flight, and I've put a little drip tray down at the trailing corner where the oil flows before it drips off the gear door. It makes me feel like I've got a real oil-guzzling radial engined warbird in my hangar!

[Piloto]

I have the M20 separator on my M20J and I am very happy with it. Not a single drop on the door or the belly. It also helps on reducing the oil consumption.

José

[Deb]

We wipe off the gear door and breather tube after flight. We also put a paper towel in the breather tube when we're not flying. We clip a "remove before flight" streamer on the paper towel and another on the pilot seat or flap switch so we don't forget to remove it. The oil over time will damage the paint on the bottom of the gear door if it's allowed to remain there.

[N201MKTurbo]

If it stops dripping, you are out of oil...

[Andy95W]

My oil breather drips oil on the nose gear door. Any way to prevent/minimize the drip and/or the staining on the door?

IMO, just wipe it off the door when you put your airplane away.

And be glad you're not putting corrosive combustion byproducts back into your engine.

[aaronk25]

IMO, just wipe it off the door when you put your airplane away.

And be glad you're not putting corrosive combustion byproducts back into your engine.

Really...not to start a debate but you state that as fact.....would you like to clarify and offer that as your opinion or can you point to some testing that shows the corrosive tendency of breather tube oil mist?

[Tommy]

Lol. You are!

Ain't no expert on oil separator and have no experience with it but take a look at Mike Busch EAA webinar on excessive oil consumption. He often recommends the owner to have it removed.

[Guest]

Really...not to start a debate but you state that as fact.....would you like to clarify and offer that as your opinion or can you point to some testing that shows the corrosive tendency of breather tube oil mist?

Nitric acid as a by product of combustion ends up in the oil sump where it can lead to corrosive damage to metal.

Clarence

[DonMuncy]

I'm a real Mike Busch fan, and believe virtually everything he says. However, I disagree with his stance on air oil separators. I understand that the "stuff" in the crankcase is corrosive, but the breather doesn't push all the bad stuff out and keep the good stuff. So if you "reclaim" the oil and push out the vapor, I don't see where you are any worse off. Naturally, I have never seen any studies done to prove or disprove either way of thinking.

[Andy95W]

Really...not to start a debate but you state that as fact.....would you like to clarify and offer that as your opinion or can you point to some testing that shows the corrosive tendency of breather tube oil mist?

No, you're right, I don't know it for a fact. But I think Mike Busch has a good point, whether or not it is substantiated, and I believe Clarence (M20Doc), who has more A&P experience than me.

But even more than that, adding a quart of oil every 3-4 months is pretty cheap, and cleaning my belly once a month is free, and gives me a good chance to look at my airplane and drink beer at my hangar. Compared to even the POTENTIAL of putting bad stuff back into my engine, I don't think it's worth it, IMHO.

[aaronk25]

I like to drink beer too....

[Loogie]

Insert a plastic tube that reaches down to the pan, it will drain into you pan and will be obvious that you have to remove it along w the pan when you are pulling her out of the hangar.

[Piloto]

I am on my third engine with the M20. The previous ones made it to 2000hrs with no top overhauls and high compression. I live in FLL and had no corrosion issues. It is nice to see a clean dry belly with no oil stains. I understand the corrosion concerns but keep in mind that there is much more oil inside the engine than any other chemical in it. Engine corrosion starts on the cylinder fins not inside the engine. If you want some advice about corrosion talk to a salt water boat owner. They really know about corrosion.

José

[marky_24]

Wouldn't it be easy enough to collect some oil out of the separator and send it in for analysis?

[ArtVandelay]

I don't understand the reason for the oil breather in the first place, when I remove the dip stick to check the oil level after a flight, I see water vapor, lots of it, I now if not in a hurry remove the stick and let it escape after a flight.

To clarify, I know it releases pressure in the crankcase, but why do aircraft engines need this and not automobile engines?

[N201MKTurbo]

Auto engines need it also. Because of environmental regulations they are not allowed to vent it overboard they use a device called a PCV (Positive Crankcase Ventilation) valve. It recycles the crankcase gas into the intake manifold.

[chrisk]

I don't understand the reason for the oil breather in the first place, when I remove the dip stick to check the oil level after a flight, I see water vapor, lots of it, I now if not in a hurry remove the stick and let it escape after a flight.

To clarify, I know it releases pressure in the crankcase, but why do aircraft engines need this and not automobile engines?

 

I go as far as removing the oil cap. --But only when putting it away in my hangar.  When going elsewhere and sitting on the ramp, the system stays sealed.

[dtoelke]

I'm a real Mike Busch fan, and believe virtually everything he says. However, I disagree with his stance on air oil separators. I understand that the "stuff" in the crankcase is corrosive, but the breather doesn't push all the bad stuff out and keep the good stuff. So if you "reclaim" the oil and push out the vapor, I don't see where you are any worse off. Naturally, I have never seen any studies done to prove or disprove either way of thinking.

 

'Acid' is only an acid when it is dissolved in solution.  This allows the individual ions to disassociate and become corrosive.  It's not the nitric acid that's the enemy here, its the water vapor (which enables the HNO3 to become corrosive).  That's the whole point of a separator.  It effectively DOES push out the 'bad stuff' (water vapor) while keeping the 'good stuff' (oil).  The presence of HNO3 in the oil is a non-issue as long as water content is kept to a minimum.

[mooniac15u]

Nitric acid is hygroscopic. It will pull moisture out of the air. It is effectively impossible to keep it dry in a non-sealed system.

[StevenL757]

We wipe off the gear door and breather tube after flight. We also put a paper towel in the breather tube when we're not flying. We clip a "remove before flight" streamer on the paper towel and another on the pilot seat or flap switch so we don't forget to remove it. The oil over time will damage the paint on the bottom of the gear door if it's allowed to remain there.

Exactly what I do on my Ovation. I used to leave just enough length of the paper towel sticking out of the breather tube so I'd see it on external walkaround, but added a red streamer as well to call my attention to it better (after I nearly left one in).

My Airwolf was taken out when the old engine came out recently. It was installed for about the first 3 hours on the new engine, but quickly came out again due to it generating excessive crankcase pressures, so I'm back to the default configuration. Once the Airwolf was removed, crankcase pressures measured by an airspeed indicator dropped to zero.