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  1. #1

    Post Buzzing sound on takeoff with Silverado Duramax TSB PIP4826?

    From the day I test drove the truck (I have never owned a Chevy Duramax before been with Cummins for past 10 years) I heard a buzz noise coming from the dash/engine compartment.

    The salesman said it was normal and all of them did it. Well that was good for me as it was a new truck bla bla bla. But then with the integrity issues I have had with that dealership and salesman (some of you may have seen other threads where they lied about simple things like the truck having a diesel owners manual supplement) I decided today to look it up.

    I didn't find anything on it here but I did find it on a couple other forums. Turns out the sound I hear might be something a technical service bulletin has been release on, TSB # is PIP4826

    Guess I'll call my dealership that I have been working with that I trust about it and see what they say. Figured I would post about it here in case others had the same thing or knew more about it.

    Here is the main site I found the answers (hope it is ok to link to them) I just wanted you to know my source but I also wanted to make sure this forum had the info so that no one would have to go elsewhere next time. ;)
    This one even has a photo of what one guy did to fix it himself:

    - - - Updated - - -

    PS, the fix is to turn one of the hoses 60 degrees counter clockwise.
    Buy Made in USA, The job you save just might be your own.

  2. #2


    The fix is to rotate the hose closest to the center/ drivers side of the truck. The noise is a form of water jacketing as the coolant approaches the firewall. Easy fix for sure
    2011 Chevey Silverado 2500 HD LML CC/LB 4x4 LT

  3. #3


    Actual TSB

    #PIP4826: Vibration Moan Or Buzz Type Noise Heard Or Felt Inside Passenger Compartment - (Aug 31, 2010)

    Subject: Vibration, Moan, or Buzz Type Noise Heard or Felt Inside Passenger Compartment
    Models: 2011 Chevrolet Silverado
    2011 GMC Sierra
    Equipped with the 6.6 Duramax Diesel Engine ( RPO codes LML and LGH )

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


    A dealer may encounter a customer concern of a vibration, moan, or buzz type noise heard from either inside the passenger compartment, or from under the hood. Noise may be described as coming from passenger side front of engine compartment, or from cowl area. The noise is heard better when the engine RPM is raised to between 2300 to 2600 RPM.


    If the customer concern fits the noise described in this PI, verify if the noise will change if slight pressure is put on the heater hoses. If the noise dissipates with light pressure applied on heater hose, rotating the heater hose may alleviate the noise.

    To rotate the inlet heater hose follow the steps below.

    Make sure engine has cooled down, and cooling system pressure has been released.
    Squeeze the clamp tangs to loosen the clamp on the EGR cooler heater hose (removal of the hose is not necessary so there should be no coolant loss).
    Rotate the hose (approximately 60 degrees counter clockwise) on the steel pipe fitting at the EGR cooler. The heater hose has a molded bend and a quick disconnect fitting at the heater core. After the hose is rotated be sure the molded bend is at the highest vertical point or approximately the 12 o'clock position. Rotate or wiggle the hose connection at the vehicle's body side to remove any pre-load in quick-connect fitting.
    Release clamp tangs to engage or tighten the clamp at the EGR cooler.
    Please see completed hose relocation below.

    Re-evaluate the noise after the hose has been rotated on the EGR cooler fitting.

    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.

  4. #4


    If it keeps up, you might have some bees under there. :D

  5. #5


    Well since my truck is only 3 months old I figured I would let the "pros" do it. I just received a phone call that they could not reproduce it. (groan) I told them how to reproduce it and told them if the engine was fully warmed up it most likely would not happen or at least be as noticeable. Then I asked if they could just go ahead and rotate the hose for me anyway as I KNOW it is happening. He said they would let the truck cool off and try it again. (hmmmm) And then he also said on this engine he doesn't think it has the issue and that the engine was made different so they might not be able to do anything. I told him it was the SAME engine as in the service bulletin and that if he needed I could send him photos etc. lol He said he had all he needed in the TSB and that he would talk to the tech again and see if they could figure it out. (shew)

    - - - Updated - - -
    3-18-2013 4:15 EDT
    Sooooooooooo, they did reproduce the issue and they do feel the noise is the hose. is the kicker folks. On 2012 models the HOSE MAY NOT BE ABLE TO BE TURNED. Thus they had to order the other hose style and said when it comes in they will install it and in the correct position.

    Just some good FYI for anyone else that might pull this thread up at a later date. If you have a newer than 2011 model and you hear the buzz sound you might not be able to just turn your hose yourself (huh huh that didn't sound right). You MAY need a different hose and then install it with the bend straight up.
    Last edited by E_HILLMAN; 03-18-2013 at 01:33 PM.

  6. #6


    Hose got replaced Saturday. If you have a 2012 with this issue DO NOT try to just rotate the hose on your own. Take it in, give them the TSB number above and have them replace the hose. My truck only had about 5k miles on it and the hose was already getting some wear on it where it was vibrating/rubbing. All sounds nice and smooth now.

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