Exhaust pipe keeps breaking clean

[CaseyNut]

My son has this 2003 Hemi 5.7 2500 with bad exhaust issue

He took it to a shop and they replaced the Y pipe. it ran good for about a week and the pipe broke.

he had it patched with some extra pipe and weld, etc... and it broke again.

what would cause this?

my gut tells me the motor mounts are worn and when the engine torques, it twists the pipe and breaks, but I'm not sure about that.

also, with the broken pipe at the Y, the truck wont stay idle on its own, I need to gas+brake at a stop to keep it running.

He is giving up on it, so I took it in.

I'm looking here for ideas.

Thanks guys'

 

[Marley]

Hmmm the hangers should allow enough play to prevent breaking.

AND I've never experienced any idle issues with straight piping.

Maybe check the downstream 02's.

 

[Bloody_Knuckles]

You can check the motor mounts by putting it in gear and holding the brake and watching for tilt.