Exhaust Manifold back pressure sensor port stripped

[Rocketman]

Good Evening,
I’m in the process of changing out the Exhaust Manifold back pressure sensor tube but the port in the exhaust on a CM 2350 ISX15 stripped. Does any one know how to fix this ? I don’t want to replace the entire manifold as it is not leaking anywhere. I’ve scroll through many posts but unable to find any thing close to.

Thanks Much

[Rawze]

have it tig welded up and re-tap it?

that, or replace the section.

[Rocketman]

Thanks Rawze, I like that tig weld idea a lot .

[J_Rok]

A helicoil might be an option as well, that’s what they are made for.

[Rocketman]

Thanks for the replies everyone. Here’s my update, for anyone who ever has this issue. I got a 12mm X1.0 tap as this is the exact thread for the nuts on the back pressure sensor tube and carefully tapped it out . While at it I rethread the port in the head as well. Started engine while the tube was disconnected to blow out the port. Cleaned both ports with brake cleaner add a little anti-seize to the threads . Works like a charm. Save me 500 bucks as that was what the mobile welder was charging to tig weld this pipe to the exhaust manifold.

[JimT]

(03-09-2025 )Rocketman Wrote:  Thanks for the replies everyone. Here’s my update, for anyone who ever has this issue. I got a 12mm X1.0 tap as this is the exact thread for the nuts on the back pressure sensor tube and carefully tapped it out . While at it I rethread the port in the head as well. Started engine while the tube was disconnected to blow out the port. Cleaned both ports with brake cleaner add a little anti-seize to the threads . Works like a charm. Save me 500 bucks as that was what the mobile welder was charging to tig weld this pipe to the exhaust manifold.

I did the same last summer, retapping the worn threads. One thing I'd recommend though is to find a plug tap (or bottoming tap) as opposed to a tapered tap. Start out with the tapered if you want but the threads of the little tube need to go nearly all the way up to the flared edge to create a proper seal. Not something you want leaking because it wasn't completely seated. Also, a high quality tap is recommended. The cheap chinese ones can result in slightly loose threads which might lead to it becoming easily stripped out again. I also ran the male threads of the new tube through a die of the same size to clean up the knicks and burrs that it came with.

[Aleeex]

And to add to this, if anyone is attempting to remove the tube - please pre heat the manifold piece with a torch and add a lubricant to the thread..