Weird Air Rushing Sound While Exhaust Braking.

[JHumphries]

Just picked up a new to me 2015 3500 dually with a little over 100k on the clock. This isn't my first rig, but I've been without a truck for almost two years thanks to... circumstances.

When the exhaust brake kicks in, there's a large air rushing sound, like lots of air leaking from somewhere. The truck still slows down as well as I remember, but... I've read a little about turbo actuators, but I'm not sure where to head with this. I don't notice any abnormal noises when the brake is off, nor at idle. I do have a 3 month, 3,000 mile warranty, so I need to move quickly.

Additionally, there's what looks like a leak on the flex coupler on the front of the EGR cooler. It's covered in soot. See attached picture. It might be kinda small. I have to figure out how to get pictures on here now. I'm not sure if those are related.



Now for the weird part: on a cold start with the exhaust brake on during warm up, the cab smells like... slightly burnt breakfast sausage and syrup. I know that sounds weird, but that's the best way I can describe it. I assume its from the EGR leak. I only notice it when the engine is not warm. i.e. stationary at a light, etc.

I think it has a double disc clutch in it based on the sounds when in neutral and when disengaging the clutch.

Somehow manual idle-up has been enabled, not that I'm complaining.

The synchros in 1st and 2nd are a bit stiff. That I can live with. Because I usually double clutch when down-shifting, I didn't notice that the synchros in 4th gear are shot. Here's to that warranty. I tried to downshift quickly and ground the absolute hell out of it, so I started playing with it to figure it out which directions they don't work.

The reverse lights are hard wired to a toggle switch on the dash straight from the battery... Not sure what that's for.

I missed a couple of things on the test drive, but I'm still fairly happy with the condition of the truck.
Now to start fixing things.

Any tips on where to start on the turbo/exhaust brake noise? Also, what should I look at, or try, for the EGR leak if it's not connected?

 

[lpennock]

The soot, noise and smell indicate you have an exhaust leak. Probably at the coupler were you see the soot.

 

[Dasmoeturhead]

The soot, noise and smell indicate you have an exhaust leak. Probably at the coupler were you see the soot.

^^^^^ Yep

 

[Ozymandias]

Torque that coupler, from my experience with these couplers they close way more then what I see on your pictures.

 

[JHumphries]

Torque that coupler, from my experience with these couplers they close way more then what I see on your pictures.

Thanks. I'll try that.

 

[JHumphries]

Well, the smoke seems to be something dripping onto the manifold or turbo when cold. It burns off during warmup. The drip is slow enough, or non-existent, that it doesn’t leak while hot. I’ll look in the morning to see if I can locate the source.

 

[EDankievitch]

I’m thinking you have a coolant leak and that is the odor you smell. I’d go over every hose and clamp. Don’t forget the ones under the burp tank. I had a small vent hose leak on my 13. They used the wrong size clamp at the factory.

 

[JHumphries]

I’m thinking you have a coolant leak and that is the odor you smell. I’d go over every hose and clamp. Don’t forget the ones under the burp tank. I had a small vent hose leak on my 13. They used the wrong size clamp at the factory.

Thanks for the tip. I wasn’t able to crawl up there this morning. I’ll look at it this afternoon while I’m putting the quick release grill parts on from Geno’s. That’ll give me somewhere to stand!

 

[JHumphries]

I tightened the crap out of the band clamp. The nut moved almost 1/2". No more air rushing while the exhaust brake is applied and 36 psi of boost instead of 32 now.
Now to find that pesky leak...

 

[Ozymandias]

Like I said, now before you search for a leak, test drive it.
It could be as simple as condensation spraying out of the loose connection that you tightened now.

 

[JHumphries]

Like I said, now before you search for a leak, test drive it.
It could be as simple as condensation spraying out of the loose connection that you tightened now.

The smoke only occurs when the truck is cold, so I'll have to wait until the morning most likely.

 

[lpennock]

You should wash off the soot so you can be sure the exhaust is fully fixed.

 

[JHumphries]

You should wash off the soot so you can be sure the exhaust is fully fixed.

I will. It was just a little hot at the moment.

 

[Ozymandias]

The smoke only occurs when the truck is cold, so I'll have to wait until the morning most likely.

Make sense as condensation only happens the first couple minutes of engine run time.