Help! Freightliner Cascadia exhaust leak.

if you have exhaust fumes coming into the cab, it's now a safety concern.

list as such, might get better results. ??

 

That hose missing off the back of your air intake box?
Most likely part of the crankcase vent or intake recirc system. On its own, it won’t blow your exhaust open, but it can mess with how the engine breathes. When you hit a regen, the engine’s working harder, airflow changes, and that can crank up exhaust temps or tweak backpressure. That just makes any existing leak show up more.

Since it only happens during a regen, the real culprit is probably a weak spot in the exhaust: joints, gaskets, or flex sections that open up under heat and pressure. The missing hose might make it look worse, but it’s not the root cause.

Try:
1. Reconnect or cap that hose so it doesn’t create secondary problems.
2. Inspect the turbo outlet, EGR, DPF connections, and nearby flanges or clamps. Look for soot, cracks, or loose bolts.
3. Document it, especially during a regen. Pictures or notes showing exactly when it leaks can make the shop fix it faster.

 

The missing piece of pipe is for the air compressor inlet. It needs to be replaced, but doesn’t have to be factory piece,any hose will work.
Make sure the cover is sealed for the hvac filter and look for black soot along the exhaust.

 

Does this truck have a grass burner or a stack out back? If it’s a grass burner check the black vents on the back of the cab with a flashlight the rubber flaps warp and you suck fumes into the cab. I’ve blocked mine with black duct tape and so have 4 guys I work with . No more fumes in Cab now I use a carbon monoxide detector and readings are gone after I did the tape. Ps boss changed the vent but they only lasted a year or so.