The exhaust system on my Cessna 180 was installed as defined in the Cessna 100 series maintenance manual. Exhaust gasses are leaking out of the slip fit joints at the middle cylinders and where the headers join the muffler coating several things with exhaust residue. Does anyone know if this is normal? Any recommendations on how to seal this?

Replaced 470 exhaust last year from stock to Knisley....No leaks nor residue, my old stock set-up didnt leak either.

Leaking exhaust systems are NOT normal and can be very dangerous--and it makes your airplane unairworthy. Not only is it possible for CO to seep into the cabin, but escaping exhaust gasses can damage nearby wiring, etc.

Cary

Not sure what you have but if it is the old style with individual pipes and clamps then I have never seen one that didn't have a minor leak at a clamp or two. They are a pain in the butt.

When I did my Pponk conversion 2.5 yrs and 365 hrs ago I sent my whole exhaust including muffler to these guys, http://www.customaircraft.com/ So far I don't have any leaks, before I couldn't stop the leaks. I highly recommend them I paid around $800 that included a new muffler.

Exhaust leaks are not cool. Apart from the obvious CO issue, the residue is corrosive... Use ManiSeal exhaust sealant on any stubborn joint leaks, it works a treat and much cheaper than rebuilding an otherwise sound exhaust system

Thanks for all of the good information. One mechanic I talked to says that this is typical of this installation, and wasn't too concerned. It really bothers me, so I am having it fixed. The leak is at the slip fit joint about three inches from the mounting flange. Maniseal and other products are rated to about 600 F. I don't have EGT gauge installed yet, but don't EGTs peak in the 1300-1400F range? Three inches from the flange, I would expect that the temps are in this range. There is one product out there called Silkolene 762 that will handle temps up to 1470 F, but it is $200.00+ per tube, while those products marketed to the common man are $8.95, but are rated to 700 F. Any experience with such products?

I just sent my Maule muffler (left side) in to Dawley Aviation in Wisconsin. Complete overhaul (100% new parts) and turned it in less than a week. Beautiful welding and it mated right up to the exhaust studs. No wrestling to get it on like the original.

Yet to be seen if it will have a greater lifespan than the original. Just based on the quality of workmanship I would highly recommend Dawley.

Mr. Ed

If you have the old stock set-up I highly reccomend looking into the Knisley exhaust. It sleeves together instead of the bolt-clamp style, no leaks. The stock risers fit inside the Knisley risers, and it was very noticeable when I changed from stock to Knisley, breathes way better. Got the overhauled Knisley from AWI for $1600 and got $250-300 in exchange for old exhaust as core (re-used my old shroud that would be an extra expense). They call it overhauled, but it was brand new steel.

While on the subject of exhaust, anyone know anything about the cone's that burn out after 200-400 hours? An A&P said he wouldn't annual a plane with the cone missing (I don't use this AP), that would mean I'd have to replace the muffler every year, and who wants that dang cone anyways! Same A&P also said something about an STC to run without the cone. I'd like to run without the muffler altogether

Are there any other options besides Stock, Knisley, or soon? to be STC'd for 56' and later model 180/182 LEES exhaust $$$? 55Wagon has the LEES on his ride and they sound bad to the bone, however thats alot of loot for some flow masters

Skalywag wrote:If you have the old stock set-up I highly reccomend looking into the Knisley exhaust. It sleeves together instead of the bolt-clamp style, no leaks. The stock risers fit inside the Knisley risers, and it was very noticeable when I changed from stock to Knisley, breathes way better. Got the overhauled Knisley from AWI for $1600 and got $250-300 in exchange for old exhaust as core (re-used my old shroud that would be an extra expense). They call it overhauled, but it was brand new steel.

While on the subject of exhaust, anyone know anything about the cone's that burn out after 200-400 hours? An A&P said he wouldn't annual a plane with the cone missing (I don't use this AP), that would mean I'd have to replace the muffler every year, and who wants that dang cone anyways! Same A&P also said something about an STC to run without the cone. I'd like to run without the muffler altogether

Are there any other options besides Stock, Knisley, or soon? to be STC'd for 56' and later model 180/182 LEES exhaust $$$? 55Wagon has the LEES on his ride and they sound bad to the bone, however thats alot of loot for some flow masters

My exhaust system has a manifold with the forward and rear cylinder flanges attached, and the center cylinder has a stub that slip fits in to the manifold at the center tube. It looks like a good design, but it's leaking at the slip joints. That's what I need to seal up.

Maniseal or similar works just fine, granted the temp rating is not as high as EGT's, but I've never had it leak on literally dozens of different aircraft.

The hardest ones to seal are turbo 206's and turbo 210's but I've had 100% success using sealant. On the turbo exhausts be careful to only apply it to the outside of the pipes before fitting the clamps and slide slip joints together a little before applying it to the pipe. Just so there's no chance of a chunk breaking off and getting eaten by the turbo

As mentioned, much cheaper than rebuilding an otherwise sound exhaust!