Hi guys, my first post.... this site is great - lots of good information. Gotta question(s) for you...

1999 2500 auto, a/c, 4.10 rearend, 5.9 24V, about 130k, Holset HX35W turbo, ISB 215 model engine, stock tires, stock everything!

I just started getting a bad whistling noise. it comes on strongest under acceleration and minimizes while at a constant load. starts around 1400 rpms. gets worse when the engine warms up. seems to minimize after about 2100 rpms. doesn't seem to be grear specific or rpm specific but more prevalent when a demand on the engine occurs. difficulty trying to elicit it in park with no load but can hear it slightly.

Checked exhaust manifold bolts and they appear tight. checked all the clamps arounf the turbo and they were tight. even sprayed soapy water on them to look for bubbles. took the intake boot off the turbo - some black soot but not real bad. no evidence of oil. blade had described play but it didn't rub against the housing. no abnormal exhaust smoke. it really sounds turbo related because when accelerating and letting off the throttle i can hear what i think is the whistle from the trubo spooling down. this is a new noise?

any ideas? thinks its my turbo unit? thanks for your input.....

 

Bob, is this a new vehicle for you, or have you had it a while and are accustomed to the various noises? It could be a leaky boot at the intercooler entrance or exit. You might want to check there for boot wear and clamp tightness. Check all along the air path to the intake horn on the engine for loose clamps or damaged boots.

 

i've had it since new and this is definitely a new noise.....

 

Maybe one of the crew in here snuck out in the night and silently lifted your silencer ring out of the turbo. I would check with Hoss to see if he's been running surreptitious night missions again

 

Have you noticed it since replacing your air filter? Also, check the duct boot between your air box and fender. When you remove this you can hear the turbo whistle louder even with the stock filter...

 

plug both ends of your after cooler and charge to 30lbs and see what you get

 

I'm willing to bet it's a loose intercooler boot clamp.

 

Ok, this might sound stupid but I had the same thing a couple months ago. I had a strange whistle/squeal that took me a couple days to locate and when I finally found it, it was a u-joint. Situaltion sounds a lot like yours so that might be one thing to check. Drive around a little bit and then get under the truck and see if one ujoint is a hot. If so, theres your culprit.

blueandsilver02

 

Well guys, thanks for your help. I finally found the problem. It was a loose, and REAL LOOSE, rubber hose clamp at the downstream side of the aftercooler before it ascends up to the intake manifold. No squeal/whistle and power is back...... Thanks

 

Excellent!