Cabin Heat Control

[gemiller]

Our muffler failed in flight and after repair we find the cabin heat control is stuck. Did the heat from the unmuffled exhaust do something to the cabin heat cable to jam it closed? Any insights are appreciated.

 

[Piper J3]

You don't give a lot of details here.... but yes, it's possible.

 

[gemiller]

The exhaust system failed at the number 3 cylinder exhaust pipe/ muffler interface. It failed in flight and made a big mess inside the engine compartment from exhaust gases. Most of the mess was under the engine where the cabin heat cable runs from the firewall to the back side of the liquid coolant radiator. We observed the cabin heat cable being stuck upon the post repair test flight. The door behind the radiator seems to be able to move but the knob inside the cabin is stuck closed.

 

[Avanza]

The exhaust system failed at the number 3 cylinder exhaust pipe/ muffler interface. It failed in flight and made a big mess inside the engine compartment from exhaust gases. Most of the mess was under the engine where the cabin heat cable runs from the firewall to the back side of the liquid coolant radiator. We observed the cabin heat cable being stuck upon the post repair test flight. The door behind the radiator seems to be able to move but the knob inside the cabin is stuck closed.

The plastic inside the cable has most probably melted and wire is stuck, you need to replace them.

Good luck

 

[gemiller]

The plastic inside the cable has most probably melted and wire is stuck, you need to replace them.

Good luck

That is what I was afraid of. Thanks.

 

[gemiller]

I actually managed to work it free.