exhaust leaking?

[dcastor]

Went to the hangar today to do an oil change.  Saw a spot on the cowling that looks like a rough white film.  I think it looks like exhaust byproducts. In the same area in the exhaust I saw a bronze discoloration.  Is this signs of an exhaust leak?  Please see attached photos.

[Marauder]

Went to the hangar today to do an oil change.  Saw a spot on the cowling that looks like a rough white film.  I think it looks like exhaust byproducts. In the same area in the exhaust I saw a bronze discoloration.  Is this signs of an exhaust leak?  Please see attached photos.

I had a slip joint replaced last annual that was doing what your last picture shows.

Sent from my iPad using Tapatalk

[Mcstealth]

The last time you had the cowl off, was there any of these signs?

 

[bonal]

Remove the cowl take a shop vac wrap a wet towel around the hose end and make a good seal into the end of the exhaust pipe plug the hose into the out of the vacuum turn it on and use a spray bottle with soapy water and spray around the pipes looking for bubbles

[3914N]

First-time owner here... how much does an exhaust leak inside the cowling cost to repair?  It seems like it could easily be anywhere from $50 to $500...

[carusoam]

For an NA exhaust that is a good estimate to weld up a worn seam.  For a TC exhaust some clamps cost more than that.  They may need to be changed out each time they get loosened.  I had the exhaust tip seams welded in my C.  Something had aged poorly over 40+ years...

Exhaust stains are usually easy to find and repair the issue that is causing them. A leak in a TC system can be as serious as a cutting torch depending on what is causing the leak.

two issues that can be a problem.  A fire up front or carbon monoxide being let into the cabin.  Not being aware of each problem, if they were to start, would be bad.

there are a few companies that are specialized in exhaust system construction.  They are both materials experts and welding experts.  You can probably find a couple of people/threads here or in the Trade-a-Plane advertising section.

One odd rule of rebuilding an exhaust system it takes a small part to be original and the rest can be completely added as needed.

how does that sound?

Best regards,

-a-

[Yetti]

so can someone correct me?  That looks like a slip joint?  does a slip joint maybe just need cleaning?   Put some mouse milk in there, take it apart, clean the gunk out, put some mouse milk on it and put it back together.   Then when it heats up, it should seal up.

[Piloto]

Check for loose nuts at the flange of the exhaust pipe. It appears that the pipe was not fully inserted at the time of installation. You can put a clamp similar to the one on the left rear cylinder.

José

[Guest]

8 hours ago, Yetti said:

so can someone correct me?  That looks like a slip joint?  does a slip joint maybe just need cleaning?   Put some mouse milk in there, take it apart, clean the gunk out, put some mouse milk on it and put it back together.   Then when it heats up, it should seal up.

Exhaust slip joints tend to wear over time, it's a normal process.  The only ones which don't wear are the ones which are seized.  The seized ones tend to crack.  The slip joint can be replaced by an approved welding shop.  Proper assembly with some high temperature anti seize paste and regular application of Mouse milk helps.

Pressure checking with a shop vacuum will locate the leak.

Clarence

[Yetti]

Thanks for the help.  How often should anti seize be applied?  Annual time or oil change?

[Danb]

Did oil change today and noticed this exhaust leak  don’t know if it from flange above or a pinhole or crack? Also my lucky day first oil leak.

[Cruiser]

I am replacing my four year old Dawley overhauled muffler with an AWI overhauled muffler because one end of the muffler was cracked along the top and bottom length of the end plate. Everything else on the muffler looked in good condition.

Would this be caused by normal heat/cool cycles or something else? 

[carusoam]

A twofer Dan...

oil and exhaust..:

One thing to keep in mind... the Bravo exhaust system is under higher temp and pressure than a N.A. engine.

This makes the exhaust leak a very important find. This might simply need a new seal...

Where the Bravo usually has a challenge is after the three individual exhaust streams combine on each side... this is where the average EGT starts to be higher...  this environment thins the exhaust tubes and can weaken their structure... 

A leak prior to the TC can become blow torch like...

So don’t Wait to to get this one looked at...

Good luck finding the sources of both leaks...  the pics show various parts of the TC with oil dripping... might be time for some new TC seals?

Follow-up question... Were you able to sense an elevated CO in the cockpit?

PP thoughts only, not a mechanic...

Best regards,

-a-

[Shadrach]

3 hours ago, Cruiser said:

I am replacing my four year old Dawley overhauled muffler with an AWI overhauled muffler because one end of the muffler was cracked along the top and bottom length of the end plate. Everything else on the muffler looked in good condition.

Would this be caused by normal heat/cool cycles or something else? 

4 years is a lousy life span for an exhaust system. They often go to TBO. Have you spoken to Dawley about the failure?

[Danb]

Anthony the oil dripping seem to be the push rod above cyl no 4 with the oil dripping down then in any direction it likes.

[1964-M20E]

Flying home form the Mooney Summit I noticed my Senesrcon was reading 20 to 30ppm CO usually it reads 5ppm or less.  I pulled the cowling and found that #4 flange gasket was leaking.  All 4 gaskets were replaced over the weekend because you can't get one off by itself with the slip joints.

[Danb]

That’s interesting John, mine read higher on the ground, it’s alwasy zero in the air,on the way home from the Summit it was reading 3 or 4 parts not a big deal but maybe it’s the leak like your was hmmm.

[1964-M20E]

High readings on the ground are not a concern for me with the door open etc.  I am concerned about cruise mode.