2003 Cummins engine whine @2000+ RPM's ( Solved/Muffler?)

[lbond01]

I have a 2004 Bounder Diesel on a 2003 freightliner XC with a Cummins 5.9 ISB. I had a over heating problem. I found the cooling fan had chunks missing on some of the blades. Had to remove radiator/charge cooler to get to it. Radiator was rebuilt and cleaned out (was plugged up). They tested the charge cooler and they said it looked like a sauna in the test tank. Replaced Charge cooler and both cold side boots. Got everything back together and now I have a high pitched whine that starts at 2,200RPM's and up and is pretty load (see video). Someone suggested that muffler was plugged up. Disconnect muffler and sound is there still. I have used a mechanics stethoscope to listen to turbo and alternator. They both sound normal. The sound kinda sounds like it is coming from rear bottom of the engine near fan. Maybe belt tensioner roller? Anyone ever heard this sound?
Fan blades

5.9 ISB whine

[Flan]

A cac leak sound reminds me when we were kids you would put a wide piece of grass between your 2 thumbs and blow through them using grass as a reed. Same screech.

[ScottG]

A Cummins with no muff will have a hideous drone on the highway.
Besides, a big 6 without a muffler sounds terrible to me, something like the kids and their open exhaust Honda's except a bit lower tone.

[lbond01]

Stop the press, found the problem!! Everyone was tell me to focus on the turbo CAC. That what it was, the coupling on the CAC to the long turbo outlet pipe. The clamp was hand tight. Tightened it up and noise is gone. I can't believe that much noise came from that turbo leak. I will inspect the muffler while I have it out. Has anyone gone to a straight pipe instead of muffler? With the muffler out, it doesn't seam that loud. Thanks for all the help, I was getting ready yo pull the belt tensioner!

[lbond01]

Video was taken in driveway. It makes the same noise going down the road. Boy is it loud when you are accelerating on the onramp with a sound wall next to the road. The fan is a fixed blade with no clutch, which was replaced with factory OEM part.I will check all my boot/couples connections again. The clamps for the couplers were replaced with the upgraded design, which has a bigger spring. On the boot to the charge air cooler I had to modify the clamp (remove washer and bend stud), I will go back to the old clamp tomorrow. Thanks for all the ideas!!

[Corkey05]

centerline wrote:
a whine in a diesel engine is usually 1 of 2 things... turbo bearings, or a leak in the air charge system.

when the air charge system pressurizes, a pinhole in a humphose, or a loose clamp can make an irritating whine....

both the turbo and a leak in the air charge side will make a whine when the turbo starts working... but the best way to tell if you have a turbo issue is to pull the intake hose (air cleaner side) off of it and wiggle the shaft... if it has any side to side play, the bearings are on their way out... but a little end play can be normal.

if the turbo checks out good, then you will will have to check all the rubber hoses in the charge side of the turbo....

if you can get it to whine while running in the driveway, use a 3-6ft length of hose and hold one end to your ear and use the other end to listen to the various hoses, or other suspect items, until you pinpoint the source of the noise.

X2

Mine was a clamp, after the CAC had been removed and reinstalled. A clamp at the CAC just needed to be slightly shifted and tightened - then all was good. You have nothing to lose by checking every clamp between the turbo and the CAC. If one looks a little "off", reposition it so it's straight.

[centerline]

a whine in a diesel engine is usually 1 of 2 things... turbo bearings, or a leak in the air charge system.

when the air charge system pressurizes, a pinhole in a humphose, or a loose clamp can make an irritating whine....

both the turbo and a leak in the air charge side will make a whine when the turbo starts working... but the best way to tell if you have a turbo issue is to pull the intake hose (air cleaner side) off of it and wiggle the shaft... if it has any side to side play, the bearings are on their way out... but a little end play can be normal.

if the turbo checks out good, then you will will have to check all the rubber hoses in the charge side of the turbo....

if you can get it to whine while running in the driveway, use a 3-6ft length of hose and hold one end to your ear and use the other end to listen to the various hoses, or other suspect items, until you pinpoint the source of the noise.

[ScottG]

Doesn't really sound like a boost leak to me the way it comes on and the frequency of the sound itself but my hearing sucks.
That video was made with the vehicle parked wasn't it? If so then it wasn't building any boost. Needs to be under load to do that.

[Flan]

Maybe a leak in the cac system, only whistles when the turbo is up on boost.

[ScottG]

That's awful!
Never heard that before but it seems to come on about the time the fans starts to freewheel hard.
Did they replace anything to do with the clutch for the cooling fan and is it a Horton?
If it wasn't replaced, I wonder if the out of balance broken fan damaged it.