Oil leak

MooneyDriver78

MooneyDriver78

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Tom
So it looks I have an oil leak from cylinder 1 on my io360, or maybe it's coming from somewhere else or is just spilled oil, here is the photo of lower spark plug, any thoughts?
I found oil dripping from various lower front parts of the engine, but don't know if it just collected there, found in another forum they recommend checking the pushrod.
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Most likely a push rod tube or a valve cover leaking. Clean it fly it for 30 minutes and inspect again.
 
good luck ever getting that exhaust nut off! Is that red stuff rtv??
 
Vaflier said:
Most likely a push rod tube or a valve cover leaking. Clean it fly it for 30 minutes and inspect again.
Click to expand...


Check the valve cover bolts, that's a easy one.

I'd wager a beer it's a pushrod tube, those things love to leak.
 
James331 said:
Check the valve cover bolts, that's a easy one.

I'd wager a beer it's a pushrod tube, those things love to leak.
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I'll check those spots, I don't think it's the valve cover, it looks clean from the pix I took:
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I'm no mechanic, but if that pipe to the left of the spark plug is the intake, it almost seems as if the oil is coming from behind it based on the discoloration. I'm used to seeing wet oil however this is all burned off what I can tell (which is admittedly precious little). Also, it looks like oil is pooling on the lower lip of some of the fins on the cylinder and being blown up (or down) in little rivulets. I don't know which way the air flows in that spot, but if the direction of air flow is up, that would seem to support my theory about where the oil is coming from.
 
iflyvfr said:
I'm no mechanic, but if that pipe to the left of the spark plug is the intake, it almost seems as if the oil is coming from behind it based on the discoloration. I'm used to seeing wet oil however this is all burned off what I can tell (which is admittedly precious little). Also, it looks like oil is pooling on the lower lip of some of the fins on the cylinder and being blown up (or down) in little rivulets. I don't know which way the air flows in that spot, but if the direction of air flow is up, that would seem to support my theory about where the oil is coming from.
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To give you an idea how much the oil can travel...I found a small pool of oil from belly aft of the cabin, I pulled the belly panel and it was migrating down the rudder control rods, dripping off the rod couplings where the rods turn upwards. In the picture you see a brass colored air intake thingy below the red alternator, it had oil dripping from it. In general the air should flow down thru the fins and out the bottom, but with all the pipes,wires it's probably pretty turbulent underneath. Hence the reason why I asked where to look for the source.
Also, the oil was changed 2 weeks ago, plane has 15 hrs on since then, they washed the engine down with mineral spirits afterwards, I checked the filter was still safety wired.
I'm going to have a mechanic look at this week but wanted to do some detective work first.
 
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There are a couple things you can do. Wash the engine again and add UV dye to the oil, or spray all suspected areas with athletes foot spray and run it for a few minutes. Oil leaks show up like a big neon sign. Works like crack developer in a dye pen test.

The spray approach works better IMHO.
 
Who built the cylinder? I'd clean it up with stoddard solvent and inspect it for a head crack or separation. See any signs of exhaust gas residue? Maybe ask your mechanic whether a compression test with soapy water is warranted. That opinion is influenced by the recent separation of an 0-320 cylinder on a plane I sold to a friend. Better safe than sorry.
 
Stewartb said:
Who built the cylinder?.
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Engine was factory new in 1996, got about 1800+ hours on it.
Also, not sure it's related, but my CHT probe in cylinder 1 went bad, which is what prompted me to give the engine an inspection in the first place.

One more question, I have a Mccauley CS prop, if it was leaking, without removing spinner, where would I look to check it?
 
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