1979 M20K 231 Exhaust Leak

[231DF]

Hey All, 

I have an exhaust leak from the circled joint. It's blowing out towards the front of the aircraft (In flight its being pushed out of the cowling at the cowl flaps joint.
My A&P suggested we leave it, any suggestions here on how I can seal it up bar replacement of the full exhaust system? Engine is a TSIO360LB

Thank y'all!
 

[anthonydesmet]

Pretty common for the 231 in that location.  I’ve had my old one welded a few times. One of the times it burned a hole through my lower cowling. A couple annuals ago I found a new one and took off my old one had it welded and now keep it on the shelf as a spare.  It’s not going to get better plus with an exhaust leak, carbon monoxide is always a concern.  I’d find someone that can repair it.

[natdm]

For future reference, this would probably be better in the new M20K section. 

Also, I'd find a new A&P that doesn't encourage ignoring exhaust leaks.

[EricJ]

Does it leak all the time or only at startup?   Many of the exhaust joints leak like crazy at startup and then seal when the pipes get hot and expand.    Your A&P may be saying he thinks it's just a startup leak.

[231DF]

@EricJ I think that the theory my A&P has is as you said, the exhaust seals when the pipes get hot and expand sealing up. 

I'm 50/50 on this theory as there was some evidence of exhaust on the cowling, specifically on the cowl flaps, stemming from where the cowl flaps pivot in a white streak.

Having spoke to a couple A&P's someone suggested the use of a ball peen and a sandbag to open up the pipe very slightly and tighten the fit. I'm still very much undecided. 
 

[Slick Nick]

11 hours ago, 231DF said:

@EricJ I think that the theory my A&P has is as you said, the exhaust seals when the pipes get hot and expand sealing up. 

I'm 50/50 on this theory as there was some evidence of exhaust on the cowling, specifically on the cowl flaps, stemming from where the cowl flaps pivot in a white streak.

Having spoke to a couple A&P's someone suggested the use of a ball peen and a sandbag to open up the pipe very slightly and tighten the fit. I'm still very much undecided. 
 

It’s worth a try. 

[anthonydesmet]

12 hours ago, 231DF said:

I'm 50/50 on this theory as there was some evidence of exhaust on the cowling, specifically on the

I’d think I would want to answer if the exhaust leak is impacting you in the cockpit. Maybe get a reliable digital carbon monoxide detector and see what your levels are at startup, taxi and in flight.  Might help you address the immediate safety level of concern you should have.

if your pushing high levels in flight then that will give you your answer not only if you’re A&P is correct but change your 50/50 position to 99/1.

[231DF]

11 hours ago, anthonydesmet said:

if your pushing high levels in flight then that will give you your answer not only if you’re A&P is correct but change your 50/50 position to 99/1.

Mind expanding on what you mean here? 

I have a digital CO detector onboard that's never gone over 1ppm so far. I'll look for a portable one to confirm they concur!