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i am a little new the the chevy world and i am also new the the forums but i am learning tons from everyone on here lots of good info. my local dealers are not very educated on the duramax.so every little bit of info i can find is very helpful.
My question is that when i am inside the cab of the truck i can hear a little whisleling noise, not the TURBO. it sounds like maybe a vacum leak or something i cant tell where it is coming from . it does get louder with acceleration buy you can hear it at idle also. is seems that i quiets down when the truck gets warmer but it is always there. you cant hear it from outside of the truck though only inside the cab and it is kind of faint. just thought i would see if anyone else has maybe had this kind of thing thanks.
 

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might be a vaccuum leak with the A/C and heater controls... the ones that control the vents doors or something. It's not the windows or door seals since you say you can hear it at idle..no wind noise. You might make sure your heater and A/C stuff is off or try the switches to see if the whistle pitch changes at any point.
 

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i will have to check into that, but yes i can hear it when i am sitting still in park and it will increase when i give it some throttle. it sounds like it is coming from behind the gagues in the dash on the drivers side.
 

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Do you have an aftermarket boost gauge? Could be a hole or crack in the line.
 

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no, i am running the attitude moniter. it did it before i installed the juice also.
 

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i am a little new the the chevy world and i am also new the the forums but i am learning tons from everyone on here lots of good info. my local dealers are not very educated on the duramax.so every little bit of info i can find is very helpful.
My question is that when i am inside the cab of the truck i can hear a little whisleling noise, not the TURBO. it sounds like maybe a vacum leak or something i cant tell where it is coming from . it does get louder with acceleration buy you can hear it at idle also. is seems that i quiets down when the truck gets warmer but it is always there. you cant hear it from outside of the truck though only inside the cab and it is kind of faint. just thought i would see if anyone else has maybe had this kind of thing thanks.

My truck does the exact same thing. Exactly as you described it. I though it was a leak in one of the turbo lines etc but I have tightened and retightened and there never is any difference.

IIRC the heater vontrols are controlled electronically with motors - not vacuum.

I honestly believe it is the turbo. My noise is worse since I had my PCM reflashed and Predator updated to 2.02. Word is that Predator cranked up the boost a little which would account for the noise getting worse.

Try this: The next time you are next to a guardrail or similar barrier on the passenger side - open you passenger window as you accelerate. Listen as you accelerate and deccelerate and you will hear that same whistle coming from the turbo as you build boost and lose boost.

I think it may be louder when cold due to something the the VVT is doing prior to warm-up.
 

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I honestly believe it is the turbo. My noise is worse since I had my PCM reflashed and Predator updated to 2.02. Word is that Predator cranked up the boost a little which would account for the noise getting worse.

Try this: The next time you are next to a guardrail or similar barrier on the passenger side - open you passenger window as you accelerate. Listen as you accelerate and deccelerate and you will hear that same whistle coming from the turbo as you build boost and lose boost.
I would agree with this if he was driving, but he says its at idle sitting still, there is zero boost at idle so that shouldn't affect it.
 

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I would agree with this if he was driving, but he says its at idle sitting still, there is zero boost at idle so that shouldn't affect it.
I didn't catch the "at idle" part. You are correct. Mine will do it during elevated idle, but not normal idle.

It almost sounds like a ringing in my ears.
 

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I had a situation after my autostart was installed that allowed a little bit of engine noise into the cab through a grommet on the firewall. Sometimes when wires are run through the firewall - one of two things can occur. First, if the wire is run around a grommett instead of through it, the firewall will not be sealed properly by the grommet. Second, some of the grommts have the tunnel of the grommet as well as a plug on the grommet for the inside that has a cut across the radius that allows a wire to be inserted. If the inner grommet is not properly installed or either side of the edges of the grommet are not properly seated it will allow a noticeable amount if engine noise into the cab.
 

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Play with your fan (AC) and recirc control to see if you can get rid of it, or change the tone. At the back wall of the truck, is the noise louder. You could have a resonance (whistle) in one of the pressure relief ducts (black)
 

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Document ID# 1715594
2005 Chevrolet Chevy K Silverado - 4WD


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Hiss Nose from Dash with AC On - keywords blower compressor HVAC idle #PIT3344B - (Oct 20, 2005)
Hiss Noise From Dash With AC On
2003-2006 Cadillac Escalade, Escalade ESV, Escalade EXT

2003-2006 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2003-2006 GMC Sierra, Sierra Denali, Yukon, Yukon Denali, Yukon XL, Yukon Denali XL

Except if equipped with RPO LB7 or LLY

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Customers may comment of a hiss noise coming from the dash area with the A/C on. The noise can come and go or change intensity depending on A/C system loads (outside temp, engine RPMs, humidity, etc.). The noise is normally only heard while stopped with blower on low and radio off.

Recommendation/Instructions:
The noise is coming from the A/C orifice tube. A new orifice tube will be available shortly to correct this noise.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.



GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION


© Copyright General Motors Corporation. All Rights Reserved.


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Document ID# 1715594
2005 Chevrolet Chevy K Silverado - 4WD
 

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try to see if it related to ac compressor. it will engage in defrost mode even when heat is on. if it is the orifice tube usually you can hear hissing for a few seconds after vehicle is shut off also. I dont think there is any vacuum in hvac anymore most are all electric.
 

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That TSB is for non-diesels.
 

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Could you be hearing the cooling fan on the heatsink of the stereo?
 

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I've got a whistle but I have never noticed it changed with rpm's. I am pretty sure that mine is related to the blower motor or duct work. Much more noticeable with freah air set on defrost?? Any ideas


later
 

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can you change the tone of it by playing with fan speed?
YUP, drives me nuts!!! I just haven't taken the time to take it in for that. It is one of those things that I'll have the dealer do when the techs can pad their time doing other stuff.

later
 
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