Piper Cherokee leak from cylinder to exhaust?

jmarine225

jmarine225

Pre-takeoff checklist
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Jmarine225
Upon inspecting the aircraft today I observed a dark, oil looking coating on an exhaust pipe where the pipe meets the cylinder. The pipe is dry but has this new dark spot clearly coming from the joint with the cylinder. Any idea what the issue is here and what is actually leaking?
 
How about a pic of what you’re talking about??
 
Blindly troubleshooting from the keyboard, it's most likely either an exhaust leak caused by a bad gasket or cracked flange, or possibly a leaky valve cover gasket dribbling onto it. Hearing any new ticking noises from the exhaust pulses leaking out?
 
jason gula said:
It does look a bit like this but nowhere near this extent. I’m posting a pic in the next post.
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Apparently it’s not letting me update a photo for some reason. Saying the file is too large.
 
jason gula said:
Apparently it’s not letting me update a photo for some reason. Saying the file is too large.
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Do you have an iPhone? If so, I can walk you through the process of reducing the image size.
 
RyanB said:
Do you have an iPhone? If so, I can walk you through the process of reducing the image size.
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Yes. You can send me a dm if that is easier. Thanks.
 
Click ‘Upload a File’ at the bottom of the text box.

Select the photo from your camera roll

Once selected you’ll see this ‘Show Selected’ at the bottom of your screen -
6A616E49-72B0-4070-8217-6D2B76AB7562.jpeg

Click that then click -

97139678-1F96-49B4-BF94-9A51CB797037.jpeg


And then a size option will pop up -

17EE2808-A07D-4A5E-9306-29D89E5682EF.jpeg

Click ‘Large’ and then hit ‘Done’

Notice how ‘Actual Size’ is way bigger than the others (that’s why it won’t upload here).
 
Took me a bit but here it is
 

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Cracked in two places. It's been rewelded before, but has broken again.
 
3393RP said:
Cracked in two places. It's been rewelded before, but has broken again.
Click to expand...
The exhaust pipe is cracked in two places? It appears the exhaust/oil or whatever it is, is all over the gasket area there also.
 
3393RP said:
Cracked in two places. It's been rewelded before, but has broken again.
Click to expand...
Also, is there anything in particular that would be cracking the exhaust pipes? I replaced two earlier this year. Grant it, it is a 1969 and these are prob the originals.
 
I've welded my fair share of pipes for motorcycles, snowmobiles, race cars,etc. Steel to stainless to titanium. After so many heat cycles they usually aren't pleasant to work with. Things spider. Nothing flows right. After 50 years of cycles I doubt there's anything in particular that caused them to crack.
 
jason gula said:
The exhaust pipe is cracked in two places? It appears the exhaust/oil or whatever it is, is all over the gasket area there also.
Click to expand...

Based on what I can see, the discoloration has propagated from the cracks to the exhaust flange. The flange doesn't appear to be leaking.
 
A LeafBlower or press side of clean shop vac can confirm

cracks quite easily.

Slip over exhaust outlet, turn ON and squirt soap n water.

Bubbles =
 
Magman said:
A LeafBlower or press side of clean shop vac can confirm

cracks quite easily.

Slip over exhaust outlet, turn ON and squirt soap n water. On the outside of the manifold where the leak is.

Bubbles =
Click to expand...

Just in case someone was planning on blowing bubbles into the exhaust outlet :)
 
Magman said:
A LeafBlower or press side of clean shop vac can confirm

cracks quite easily.

Slip over exhaust outlet, turn ON and squirt soap n water.

Bubbles =
Click to expand...
Unnecessary. The cracks are visible.
 
both intake and exhaust are wet.....I'm gonna go with valve cover gasket is leaking.
 
I thought there was a question of leakage at flange?
 
I’m going to ask a dumb question here, though with reason. Is the aircraft able to flown with this leak here? I’m not saying 8 hours a day, everyday, but can it be flown once or twice until it gets repaired?
 
Liquid oil is unlikely to come from an exhaust pipe to head leak unless you are burning vast amounts of oil. In my experience a leak here would look like a greyish powder. As suggested I would look for a valve cover or pushrod tube leak dribbling down. However, if it is cylinder oil replacing an exhaust gasket is cheap.

A cracked cylinder head might let some oil leak out too.
 
Snowmass said:
Liquid oil is unlikely to come from an exhaust pipe to head leak unless you are burning vast amounts of oil. In my experience a leak here would look like a greyish powder. As suggested I would look for a valve cover or pushrod tube leak dribbling down. However, if it is cylinder oil replacing an exhaust gasket is cheap.

A cracked cylinder head might let some oil leak out too.
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The picture doesnt quite show the whole thing, but upon a visual inspection it looks like it’s leaking from the gasket area where the exhaust pipe joins up. Wasn’t sure if/why oil would be leaking for that area. Upon above that area, in the area of the cylinder, is all clean with oil/sign of any leakage.
 
jason gula said:
The picture doesnt quite show the whole thing, but upon a visual inspection it looks like it’s leaking from the gasket area where the exhaust pipe joins up. Wasn’t sure if/why oil would be leaking for that area. Upon above that area, in the area of the cylinder, is all clean with oil/sign of any leakage.
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Try a compression test. A broken piston ring could cause this if there is also a gasket leak or a crack in the exhaust port.
 
RyanB said:
+1

This does not look like an exhaust gasket leak. Based off what we can see, I’m going with a leaking valve cover gasket like @Checkout_my_Six mentioned.
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There's not any oil showing around the valve cover gasket in the OP's photo. What do you see?
 
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