Oil On Lower Gear Doors

[Txbyker]

I am a relatively new Mooney M20J owner and have a question about oil on the lower gear doors.  When I fly sometimes I get a trail of oily film on the nose gear doors.  I am a fanatic about cleanliness so I use a solvent to wipe the stuff away when I land.  Can anyone tell me what this is and why it deposits there?  Was real bad today in the 100 degree Texas heat.

Russ

[ProprAire]

I've experienced the same with my M20J.  My mechanic attributed it to leaky engine carry-through bolts.  He addressed the issue at annual and the problem went away for awhile but has since returned in far smaller quantities after flights of 2+ hours.  Could it be the breather?  I usually fill the oil to no more than 6.5 to 7 qts to prevent excess amounts from going overboard.  

[Kwixdraw]

If you have an oil change coming up soon that would be a great time to really clean the engine & firewall area then look for leaks after a short ground run. Some can be very messy and hard to find at the same time. Oil return hoses from the rocker boxes are hard to see if things don't get real clean. Your A&P should be able to help point out some common problem areas. If you cowl up and fly away then look on your own, things will be too big a mess to find the problem. You have to remember there is a tremendous air turbulence going through the cowl and cooling baffles. The oil will be all over after any flight.

You might also look at breather lines. If you are overfilling the crankcase the breather will puke oil all over until it reaches it's own comfort level. You won't be able to keep it at 8 qts all the time.

[flhelo]

Also, if you have a quick oil drain it might have just a very small piece of something that is not letting it seat properly. I had this happen to me. Just made the doors oily enough to notice.  I also do not put in more than 6.5 - 7 qts of oil. The engine will find a way to seek its own oil level.  All good recomendations above!!

[bd32322]

i have also started putting in only 6 quarts of oil and no more. Anything over 6 quarts quickly gets thrown overboard across the belly by the engine. And the aircraft happily stays at 6 quarts until after about 5-6 hours of flying - when it goes to 5 quarts.

[Parker_Woodruff]

Quote: ProprAire

I've experienced the same with my M20J.  My mechanic attributed it to leaky engine carry-through bolts.  He addressed the issue at annual and the problem went away for awhile but has since returned in far smaller quantities after flights of 2+ hours.  Could it be the breather?  I usually fill the oil to no more than 6.5 to 7 qts to prevent excess amounts from going overboard.  

[Txbyker]

Thanks for the responses.  When I picked it up at the end of November I noticed my very clean and waxed plane had quite a bit of oil on the doors but that seem to subside over time.  Mine leaks down to about 6 quarts and stays there.  I have been keeping it up over 7 lately and I bet that has something to do with it.  I am about due for an oil change and will check these things out.  I do have a quick release and it was seated well when I changed it last.

Thanks

[Txbyker]

...oh one more question...I am pretty handy with a wrench and have done my first oil change.  Question - how do you wash your engine and firewall?  Just hate to get the electronics wet.

[donshapansky]

Use a kerosene fluid that is oil based with airpressure that way it cleans oil off and does no damage to water sensitive components, the smell is gone almost immediately.

[Kwixdraw]

If you are going to change your own oil be sure to clean the filter screen for the oil pickup too. Look in the FARs  to see how to log the service in your log books properly. You will want to have the service manual and AC 43.13 open nearby when you do the work just in case some friendly FAA types happen by while you are doing the legal work on your aircraft..

[jetdriven]

On our plane when we bought it there would be oil on the nose doors.  Turns out it was a couple leaking pushrod drainback tubes.  Easy fix.

[KSMooniac]

No reason to fill above 6 qts IMO, unless it is leaking quickly and you have a long way to fly.    I bet your 7th quart is getting pushed out of the breather.

Otherwise, check the mag, drain-back hoses (under the jugs) and the case bolts after cleaning everything carefully at the next oil change.

[donshapansky]

I had Maxwell put an M20 Air/Oil Separator on the Rocket, I have 75 hrs since the install in March 2011 with oil level at 12 quarts. In 30 hrs between changes I add no oil and none on the belly! Yesterday at 15 hrs since change, the stick shows over 12 qts. A worthwhile mod!

[jetdriven]

I kinda like the idea of an air-oil separator but I hear from a couple established people, that it reroutes all the acids and water vapor back into your engine too.    

 

One more thing, Our engine is the IO-360A3B6D.   Our latest thing is to add oil only when it gets to 5 quarts, and fill to 6, unless a really long flight. We only need to add 1 quart every 8-10 hours this way, and the belly stays clean.   Where do most of you add oil?

[lahso]

Quote: jetdriven

..Where do most of you add oil?

[fantom]

About the same...if under six, I add to about 6.5; if a long trip maybe 7. Works well.

In general, Don Maxwell is not a fan of the M20 AOS.

[donshapansky]

It works if you hook the return line up to where it's supposed be hooked, Don tried returning the oil to valve cover, it puked 2 qts in 30 minutes of flight.

I got a picture from RAM aircraft showing the detail of returning to the oil to the turbo scavenge pump, which was difficult to get to. It turns out all Acclaims have the same set-up as standard from Mooney.

[jlunseth]

Quote: flhelo

Also, if you have a quick oil drain it might have just a very small piece of something that is not letting it seat properly. I had this happen to me. Just made the doors oily enough to notice.  I also do not put in more than 6.5 - 7 qts of oil. The engine will find a way to seek its own oil level.  All good recomendations above!!

[MARZ]

Long trips I bring it up to 6 - 6.5  and I'll drop a quart in 8 - 10 hours - practicing in the pattern it usually wants to stay at 5 anything more gets blown out within an hour.

[fantom]

Quote: jlunseth

[KSMooniac]

Quote: fantom

[fantom]

Thanks, Scott. I've never totally trusted that quick drain.

[The-sky-captain]

Before my recent overhaul I was adding about 12-13 quarts every 25 hours. The oil was black, burnt smelling and in the summer the temps ran a little to high for my comfort. Now at 55 hours SMOH I've added only 2 quarts and the oil is nice and honey colored at the 25 hour oil change mark.

[jetdriven]

thats because of blow-by from rings.  Why are you changing the oil at 25 hours? Do you have a full flow filter?