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Anyone know what this drain hole is near?


shawnd

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Hola. Got some fluid coming out of a drain hole on the left side of the fuselage near the left wing. It's black in color. Before getting A&P to remove the belly - curious what this might be from? Any ideas?

 

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It is likely just a hole in the belly pan which acts to drain any fluid collection.  If the liquid is black in color, I would take off the belly pan and figure out where it is coming from.  It is likely oil and you would want to know its source.

Hydraulic fluid is reddish in color.

I could also be dirty water, but the consistency would not be terribly oily.

John Breda

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Stuff doesn’t usually run out of the belly panels...

The red hydraulic fluid usually collects dirt on the other side, and gels, and waits for annual for you to clean up....

If that is what you have... there are methods to fix that...

Black is often left overs from fogging an anti rust cloud in the airframe... 

Did you spray any boeshield or CorrosionX in there?

Got any faux smoking rivets to go with that?

Best regards,

-a-

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With the one piece belly, it would make sense to just remove it and look.  You may find something important, or just reassure yourself it was nothing critical.  You are not looking a the 180 screw commitment that I would have. 

-dan

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Having recently dealt with both oil and fuel leaks occurring at the very forward end of the airframe, and seeing the resultant ooze come out of considerably further aft drain holes, my answer is that it could be almost anything, from any location forward of that drain hole.

I theorize that in the belly, there is a net-but-not-consistent flow of air from fore to aft in flight, and a net-but-not-consistent slope of the panels themselves from fore to aft on the ground.  I think these inconsistencies result in fluids sometimes completely bypassing the nearest drain hole and moving further aft.  So while you may be able to tell what the goo is from its consistency - oil, hydraulic fluid, or whatever - I don't think you can tell much about where it's coming from without pulling the panel.

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31 minutes ago, MB65E said:

5606, Landing gear jack screw grease? But, I’d say normal if you’ve flown through rain or don’t keep the belly panels clean inside and out. 
-Matt

I cleaned it last week after I brought it over from KCHD especially to keep an eye out for new leaks etc.  Havent flown through rain or clouds since and the plane is in a hangar.

31 minutes ago, M20F-1968 said:

It is likely just a hole in the belly pan which acts to drain any fluid collection.  If the liquid is black in color, I would take off the belly pan and figure out where it is coming from.  It is likely oil and you would want to know its source.

Hydraulic fluid is reddish in color.

I could also be dirty water, but the consistency would not be terribly oily.

John Breda

Shouldn't be engine oil, but agree, hydraulic should be red in color.

 

20 minutes ago, carusoam said:

Stuff doesn’t usually run out of the belly panels...

The red hydraulic fluid usually collects dirt on the other side, and gels, and waits for annual for you to clean up....

If that is what you have... there are methods to fix that...

Black is often left overs from fogging an anti rust cloud in the airframe... 

Did you spray any boeshield or CorrosionX in there?

Got any faux smoking rivets to go with that?

Best regards,

-a-

Hah! I did get a full foaming/coating of CorrosionX as a preventative measure. Though its more yellow-ish and thick goo based on what I saw along the ailerons (pointed to by the guy who applied it).

If you look closely, there is a smoking "screw" to the left of it.

I am trying to avoid pulling the belly just yet as its a PITA with the antenna wires etc. But will do before next flight for sure. Hoping its not the landing gear - which should be electric anyways..

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Just now, Vance Harral said:

Having recently dealt with both oil and fuel leaks occurring at the very forward end of the airframe, and seeing the resultant ooze come out of considerably further aft drain holes, my answer is that it could be almost anything, from any location forward of that drain hole.

I theorize that in the belly, there is a net-but-not-consistent flow of air from fore to aft in flight, and a net-but-not-consistent slope of the panels themselves from fore to aft on the ground.  I think these inconsistencies result in fluids sometimes completely bypassing the nearest drain hole and moving further aft.  So while you may be able to tell what the goo is from its consistency - oil, hydraulic fluid, or whatever - I don't think you can tell much about where it's coming from without pulling the panel.

Yeah I don't believe this is engine oil btw. I see engine oil near the nose gear doors and by the blowoff drain - clear-ish in color. Just had work done to the parking brake valve/system (like you said would be red-ish), fuel selector (that would be blue unless its mixing with something else) in that area. I guess pulling the panel is the prompt thing to do. Although carusoam's hint about CorrosionX might be valid.

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I have the same model with the same belly pan. You are correct that most of the engine oil that vents from the crankcase breather by the nose gear ends up on the belly and nose gear door and is generally lighter in color. However some of it does tend to creep into the seam between the front edge of the belly pan and the fuselage. Over time it gathers dust, exhaust residue and whatever else is in your belly pan and eventually some of it works it’s way back and exits that drain hole as well as other fastener holes looking pretty black.  I find I have to thoroughly clean the inside of the belly pan cover every annual, even though my engine does not vent much oil and I wipe it down after every flight.

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Corrosion X has a tendency to dissolve lots of loose wear particles and wick them to the surface...  that’s what it does when it makes rivets look smokey....

A tiny amount of aluminum dust brought to the surface can look like a real problem...  The looks can be deceiving...

Not so deceiving when you see it again the next time... :)

So many new things to learn about ownership.... one item at a time... hopefully...

PP thoughts only, not as educated in ownership technology as some of these other fine people....
 

Best regards,

-a-

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I've been amazed at how oil seems to find its way along the inside of the belly and come out at some unexpected place.   I wouldn't rule out that it's just engine oil, but it should be fairly easy to tell the basic nature of the stuff on close examination.   Otherwise taking the belly off and seeing where it started on the inside of the belly should be informative.

 

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Okay I didn't get a chance to take it down yet, but getting some milk crates per @Bolter's suggestion to aid the process and will attempt to take it down this weekend or early next week - before I go flying.  The consistency doesn't match the engine oil - its lighter, less viscous and definitely dark/black in color.  Doesn't smell like engine oil either. A neighbor took a look and believes its grease + lubrication oozing out. I did take a look at the open belly when it was at the MSC and they definitely didn't flood it with lubrication. Neighbor also stated that it's not hydraulic fluid given its not at all red.

Will keep this thread updated.

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19 hours ago, shawnd said:

Thanks, now I am more interested in taking it down and looking. Shouldn't be dirty.... as it was squeaky clean about 19 hours ago (~2 weeks) ago.

When I finish annual, Tri Flow is dripping from lots of places as I slide the belly panel back underneath. Squeaky clean? Noooo . . . . .

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