Exhaust leak. What are the possibilities?

[hotjag1]

I can hear what I think is an exhaust leak when I drive beside concrete barriers, guard rails, etc. It's kind of a loud ticking sound.

The muffler and the pipe between the turbo and muffler seem to be pretty solid and I don't see any movement. The muffler is kind of rusty at the clamp joint and may even have a crack or small hole that I cannot see. If that is the case, I think it would be an easy fix.

On the other hand, what is the likelihood of a cracked exhaust manifold or manifold gasket being bad? I can't determine exactly where this exhaust noise is coming from.

[hotjag1]

Ivylog wrote:
Yes, there is more pressure in the manifold when the exhaust brake is on. Buy a can of PB blaster and start spraying all the nuts on the manifold and turbo every day for the next week. Hopefully they will come off without breaking the studs.

It is a compression brake, not exhaust, but I am assuming it puts as much or more pressure on the manifold also. Thanks for the suggestion of spraying the nuts with PB blaster. I will start doing that.

[Cbones]

Disregard deleted post

[Ivylog]

Yes, there is more pressure in the manifold when the exhaust brake is on. Buy a can of PB blaster and start spraying all the nuts on the manifold and turbo every day for the next week. Hopefully they will come off without breaking the studs.

[hotjag1]

Okay, I checked everywhere that was suggested. I found soot at the head to manifold on the two middle cylinders. No soot anywhere else. The noise is definitely louder when the compression brake is on. Is this common with a head to manifold leak?

[Ivylog]

Even if it's just an exhaust gasket, on a 03 engine I'd probably replace the manifold while apart. The labor of getting it off/on will be more than the cost of a new manifold if non of the bolts break. Not sure if I'd go with one from China.

[wolfe10]

Easy to check with the engine OFF (and cold). Just use a flashlight looking for soot trails:

Head to exhaust manifold, manifold itself, manifold to turbo and turbo to exhaust.

[hotjag1]

Thanks for the suggestions. I will check out the noise difference at start up. I am suspicious of the exhaust manifold. The replies seem to point in that direction. Maybe I will get lucky and it will be just the gasket.

[Valkyriebush]

Had a similar issue and it was the exhaust manifold gasket.

[10forty2]

Old-school way to check is to have the engine running and with a short piece of old water hose, hold one end to the suspected problem area and the other to your ear....like a stethoscope. It will definitely help you isolate the exact place where the sound is coming from. Then, you can determine the cause.....

[Ivylog]

Look for black marks on the exhaust manifold as this is a known problem with the Cummings engine.

[ArchHoagland]

I've got a dime that says you have an exhaust manifold problem of some sort.

Does the noise change change as the engine warms up?

Have you stood next to the engine when it's first started and listened for strange noises on start up?

[ScottG]

Cracked exhaust manifold or a rotted out elbow after the down pipe.