Schotello

My truck is a 2001 GMC, crew cab, 1 ton dually with a Duramax turbo diesel engine.
Sometimes I hear a whistling noise coming from the front of the truck.
It does not do it when driving around town.
It only happens on the Highway.
When we go on a trip, the first 50 miles we don't hear the noise.
It starts doing is after appr 50 miles and only when my foot is on the trottle.
It comes and goes under normal driving conditrions, I am not racing and/or really stepping on the gas.
Sometimes we drive over 100 miles without the noise and all of a sudden it starts again.
The sound is sometimes loud, sometimes you can hear it only a little.
I have 150.000 km on the truck (that's around 98.000 miles I think)
It is really starting to be irritating. It has been doing it for about 1 year or so.
The truck runs fine, no powerloss, etc.
I took the truck to a garage a few times but of course the sound is not there when they try to track it down.
Very frustrating. Anyone with the same problem???

What could this be??

steiner

I cant be certain, but it sounds like the whistling may be coming from a simple whistle created by the shape of your car. It is not uncommon for different cars to whistle at different speeds. It usually comes from the side mirror area at highway speeds. Pay attention to your speed and the whistling at different volumes because it could simply be the air flowing around or through the trim of your truck. If that is the case, you can try getting some after market items on your truck to change the airflow patterns. Grill guards, after market fog lights, rain drip guards all can help. Also, if you have a good steady hand, you can try some caulk or adhesives to fasten or seal and loose trim.

Hope this helps

Schotello

Hi Steiner, thank you for the reply. It's not a wistle created by the shape of the truck.
When I take my foot of the gas-pedal the wistle will be gone instantly.
It also has nothing to do with speed as it makes no difference how fast I go.

(I once owned a Camero with a "shape-wistle", it was in the car's mirrors.
This is different.)

We suspect it's turbo related, maybe?
But we don't know where to start looking to fix it, or at least try something and where........

steiner

Oh ok, well in that case I am sorry I can't help. Takes me long enough to the my own engines, cant help you work on yours. Hopefully one of these car savvy dudes sees your post and can help. Good luck

BALLGreen

it could be your exaust blowing, when you accelerate if it gets louder it is probably, almost definetly this problem

Schotello

Would that be under the hood and somehow relate to the turbo?

thomatt12

I agree! It might be a problem with your exhaust system. Take the time to check it or have it checked by an expert.

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jkgray80

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[/align]- 6.6 LB7 Diesel Engine - P0102 , P0103 , P0236 Smoke Hesitation, Whistle , Hiss - kw acceleration drive DTC GMT560 GMT800 GMT4500 GMT5500 idle low performance turbocharger whine - (Nov 26, 2003)

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Subject:
Service VME - 6.6 LB7 Diesel Engine - P0102, P0103, P0236, Smoke Hesitation Whistle or hiss noise



SERVICE VME
This is a service VME going out for all 2001 through 2004 Chevrolet Silverado, GMC Sierra 2500 HD, 3500 trucks with LB7 Duramax diesel engines, as well as 2003 to 2004 Chevrolet, GMC 4500 and 5500 trucks with LB7 diesel engines. This message is in regard to Duramax turbocharger noises or possibly a performance or a fuel economy complaint. Excessive turbocharger or whine noise could possibly be caused by a leak in the turbocharger system. The source of the leak can be identified by using the charge air cooler system pressure testing tool, tool number J46091. The noise will most likely be coming from one of the CAC system hose connections. The suspect hose connection should be removed to complete a visual inspection of the pipe or CAC inlet. If no damage or flaw is detected, reinstall with special attention to the clamp placement in tightening procedure. Note: the charge air cooler itself can be the source of noise and should be checked by following the pressure decay test instructions with J46091 tool. Any of these issues can cause a noise or performance or fuel economy complaint and may not set a DTC. .

Models:
((2001 through 2004 Chevrolet Silverado) and (GMC Sierra 2500 HD and 3500 trucks with the LB7 diesel) and (2003, 2004 GMC C4500 and 5500 trucks with LB7 diesel) )
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BLACKSNAKE427

I WOULD HAVE TO AGREE WITH THE TURBO SYSTEM. WHEN YOU ACCELERATE SO DO THE TURBO. JUST DEPENDS ON THE LOAD- HILLS OR FLAT ROADS OR JUST SPEEDING UP. FIRST THING I WOULD DO IS GO AND TIGHTEN ALL YOUR HOSES CONNECTING YOUR TURBO PIPING TOGETHOR AND YOUR INTERCOOLER, BASICALLY FROM TURBO TO INTAKE MANIFOLD. THESE HOSES AND CLAMPS GET HOT AND COLD (WHICH WOULD MAKE SENSE AFTER 50 MILES OF DRIVING) ANOTHER WORD EXPAND AND CONTRACT ALSO VIBRATIONS AND THESE CLAMPS TEND TO LOOSEN UP. FROM THE INTAKE FILTER TO THE TURBO THERE IS NO PRESSURE JUST SUCTION. FROM THE TURBO TO THE INTERCOOLER AND FROM THE INTERCOOLER TO THE INTAKE MANIFOLD IS ALL PRESSURE THAT THE TURBO PRODUCES. IF ALL HOSES ARE TIGHT I WOULD HAVE THE INTERCOOLER LOOKED AT SOMETIMES THE TURBOS CAN PRODUCE LARGE AMOUNTS OF PRESSURE AND I HAVE SEEN THEM CRACK THE STOCK INTERCOOLERS. THE ONLY WAY TO FIX THAT IS TOO BUY ANOTHER INTERCOOLER BUT I WOULD BUY AN AFTERMARKET ONE SAY FROM BANKS POWER. IF YOU GO TO THIS SITE YOU WILL SEE WHAT I AM TRIING TO SAY. THE END CAPS OF THE STOCK INTERCOOLERS ARE PLASTIC AND ARE HELD TO THE "COOLER" PORTION BY LITTLE METAL TABS AND CAN NOT HANDLE THE HIGH PRESSUREFO THE TURBO VER AND OVER AND OVER- SOMETHING HAS TO GIVE. THE BANKS INTERCOOLER IS ALL ALUMINUM AND IS WELDED TOGETHOR NOT TO MENTION IT WILL LOWER YOUR EGT'S AND CREATE MORE POWER AND MAKE YOUR TURBO LAST LONGER. YOU DONT WANT YOUR EXHAUST GAS TEMPATURES TO GET TO 1200 DEGREES CAUSE YOU WILL FRY YOUR MOTOR. SO CHECK ALL CLAMPS IF THOSE ARE TIGHT I WOULD CHECK YOUR END CAPS ON YOUR INTERCOOLER. GOOD LUCK

Schotello

Thank you both for your input.
I have it checked and let you know.