Unusual “squealing” noise on deceleration

[gsbrockman]

On January 17th, I left out for what would turn into a 5,980 mile hauling extravaganza.

During my time on the road, White Lightning developed a “squealing” noise on deceleration......almost exactly around the same time the exhaust brake began engaging. Lightly touch the accelerator and get back into the throttle.....and the noise is gone. Additionally.....I’ve never encountered any turbo malfunctioning and have not encountered any CEL’s.

This “squealing” noise, however, began as somewhat intermittent in nature, but became more consistent as time and miles went by. For some of you old school guys....the squealing noise is very much likened to a late 70’s GM pickup blower motor squeal.

Is it possible that the “negative” torque being applied through the serpentine belt is a possible source of the noise? The serpentine belt is OE at 196k miles, but actually looks good. I went over 260k miles on the serpentine belt on my 2014 3500. I also suspect there might be an issue with either the idler pulley or the belt tensioner and/or tensioner pulley....along with the serpentine belt.

Has anyone else experienced issues similar to what I’ve described? I do have a new Dayco idler pulley and a new Dayco belt tensioner.....my plans are to release the tension on the belt tomorrow and see if I can determine an issue with the idler pulley or belt tensioner/belt tensioner pulley.

 

[TRAMPLINEMAN]

My ‘14 did a very similar thing a couple months ago. When the exhaust brake would engage, it made a weird kinda squeal noise. Mine ended up being the rear gasket between the exhaust manifold and egr cooler.
Hopefully this isn’t the case with yours. That was not a fun job.

 

[AH64ID]

I would look for evidence of an exhaust leak around the manifold. There will likely be some soot developing.

 

[dieselshadow]

The serpentine belt pulls the accessories, no matter if the engine is in braking mode or acceleration mode. Those accessories can’t add power to the belt and put it into “negative torque” and pull the engine unless you have one of those funky eco-motor/generator thingies.

 

[promisedland]

Exactly what was wrong with the PX 9 Cummins in the Kenworth that I run. Exhaust leak! Drove me up the wall.

 

[kthaxton]

I don't know what the problem could be, but I agree with dieselshadow, the belt see no difference in an uptick in rpm whether it is from the application of throttle or from being induced through the drivetrain since all rotation is still coming from the crankshaft.

 

[gsbrockman]

Thanks for all of the suggestions. I shall take a look soon and try to verify if there’s any exhaust leaks....

 

[EZeis]

My 07 did that, had leaks between exhaust manifold and head. Had to replace the manifold and it was a single piece and wrapped. Talk about annoying. Lol

Earl

 

[Cummins12V98]

Must have been a HE!! of a trip!

Good luck finding the culprit.

 

[TRAMPLINEMAN]

Thanks for all of the suggestions. I shall take a look soon and try to verify if there’s any exhaust leaks....

Well, like I said, mine leaked from the rear gasket between the exhaust manifold and egr cooler. The only way you’d see any evidence of a leak there, aside from removing the cooler, is with mirrors and a light set up to shine between the fire wall and back of the motor.

 

[gsbrockman]

Took a quick peek today, just from the top, but noticed nothing. I did, however, catch a small whiff of exhaust underhood this morning, with high idle engaged and the exhaust brake on.

I have an appointment at 10:00 am Monday at Don Franklin in Somerset, KY. I hope I don’t browse the lot too much and get off task.

 

[Wayne M.]

I know it’s not realistic, unless you have friends in the right places, but the new essential and expensive tool for light and heavy is a smoke machine. I found an exhaust leak that made no noise, but let fumes in the cab with one. Take out the EGT in the EGR and plug this baby in. It was incredible. The V clamp at the turbo was loose- and there wasn’t soot there.

 

[gsbrockman]

Earlier this morning, I recalled a friend of mine that had lots of service work done at a diesel performance repair shop about 1.5 hours away from me. On a whim, I called them, explained my situation and possible issue, and was able to get in for a more accurate diagnosis.

We test drove it together, and was able to reproduce the noise. A quick inspection under the hood revealed no exhaust leakage or soot. He grabbed a scan tool and did wind up finding a “soft” code for a turbo actuator issue.

Although it has been fairly overall infrequent in nature.....he indicated he has seen this on a few trucks in the past.

So.....it looks like I get to join the “Fail(ing) Turbo Actuator Club”.

The reman Cummins part was ordered today (Indianapolis) and hopefully it either shipped today or will ship Monday, with delivery within two days.

 

[Cummins2014]

Are you going to replace the actuator yourself, doesn't sound like its a terribly hard job to do. Do you have that scanner tool or whatever it is to calibrate it ?

 

[gsbrockman]

No.....The shop will be replacing it and calibrating it. I don’t have a scan tool and I don’t have AlfaOBD, nor do I know anyone with AlfaOBD.

 

[Cummins2014]

Good luck with it, let us know how things turn out.

 

[AH64ID]

Earlier this morning, I recalled a friend of mine that had lots of service work done at a diesel performance repair shop about 1.5 hours away from me. On a whim, I called them, explained my situation and possible issue, and was able to get in for a more accurate diagnosis.

We test drove it together, and was able to reproduce the noise. A quick inspection under the hood revealed no exhaust leakage or soot. He grabbed a scan tool and did wind up finding a “soft” code for a turbo actuator issue.

Although it has been fairly overall infrequent in nature.....he indicated he has seen this on a few trucks in the past.

So.....it looks like I get to join the “Fail(ing) Turbo Actuator Club”.

The reman Cummins part was ordered today (Indianapolis) and hopefully it either shipped today or will ship Monday, with delivery within two days.

How many miles/hours are you at now?

 

[Cummins12V98]

Time to trade it in.

 

[gsbrockman]

How many miles/hours are you at now?

196,704 miles and 3,437 drive hours

 

[AH64ID]

196,704 miles and 3,437 drive hours

Longer than many get out of theirs, but still not as long as I would like to see especially with your duty cycle. Your actuator shouldn't have issues as your use certainly cycles it!