Leaking Exhaust. Need new muffler?

[Cardiff Kook]

My exhaust is leaking. It was exacerbated by two missing nuts on my manifold (other post) but that just happened after 2 back to back four hour cross countries. I am pretty sure it always leaks as there is a white film just behind the cowling on the left side of the fuselage.

I always fly with the windows open and a CO monitor.

The muffler looks to have been repaired at somepoint. Looks like it has some JB weld on it or something.

See pics. What needs replaced or looked at?

 

[62E]

Mine was doing the same thing. I ended up having a crack in the muffler itself. The muffler would be inspected at annual, that doesn’t mean that it can’t crack or break between annuals. Knowing what I know now I’d pull the outer cover which provides your heat and inspect. I have a carbon monoxide cards card on my instrument panel and it never alarmed. Better safe than sorry.


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[DENNY]

You are looking at the heat shroud not the muffler. Are you sure that is not blow by from the whistle slot in the breather tube? Close the window and see if you get a CO2 buildup on the monitor.
DENNY

 

[Cardiff Kook]

You are looking at the heat shroud not the muffler. Are you sure that is not blow by from the whistle slot in the breather tube? Close the window and see if you get a CO2 buildup on the monitor.
DENNY

Where exactly is the muffler then? Under the heat shroud?

 

[Cardiff Kook]

And no- I'm not sure it is not blow by from the whistle slot on the breather tube. Of course- I don't know what the whistle slot is nor would I know where I would check that.

 

[62E]

Yes under the shroud. Cabin heat and carb heat are provided by forcing outside air through the shroud.


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[DENNY]

Yep, the hose clamps on the end hold it on. You may have to swing the motor but you can remove the claps and get a good look at the muffler. Do a google image search on PA 18 muffler and you see what it should look like without the shroud. When is the annual do? Should be done then.
DENNY

 

[DENNY]

Whistle slot is a hole in the aluminum breather tube. It should be about in the middle of the tube closer the the muffler so it stays warm, it is there to keep from blowing out the front seal if the breather gets full of ice in the winter and spread more oil over the plane for rust prevention. http://www.porcupinetech.com/rvproj/crankcasebreather.htm Here is one on a RV. Do a search on how to do it MTV had a post about 16 years back if I remember right. I think you stain came from the exhaust stud issue but ya never know.
DENNY

 

[Steve Pierce]

Your muffler should be inspected every 100 hrs if it has less than 950 hrs and every 50 hrs if it has more. This inspection cannot be done without removing that left hand exhaust pipe. I would talk to the person who is maintaining the airplane and ask how they are complying with the AD 68-05-01. The missing nuts could be the issue. Look for soot, usually around the clamps at the pipes to muffler connections and at the heads on intake tubes, spark plugs etc.

 

[bob turner]

I was unable to do that inspection without dropping both sides - being a bit slow, it took literally a half day (on a Super Cub - I can do a J3 in 45 minutes).

If you are paying shop rates, the smart thing is a new Attlee Dodge muffler. Make sure it terminates the AD.

A lot of shops forget this AD. Not sure why. If they do the inspection, they forget to enter it in the log. But the owner is responsible . . .

 

[Paul Heinrich]

You might want to establish a close working relationship with an experienced mechanic to walk you through basic aircraft inspection, repairs, and common troubleshooting. Participate fully in the annual inspections and IRAN repairs.

If you don’t know the basics you will be at the mercy of less honorable people than you will find here.

 

[Steve Pierce]

I was unable to do that inspection without dropping both sides - being a bit slow, it took literally a half day (on a Super Cub - I can do a J3 in 45 minutes).

I can see the flame tube on the right side through the tail pipe.

 

[txpacer]

I had problems with leaking from the muffler end clamps, so I sealed them with Flo-Ex. That seems to have solved it.