Hoot, Whine , Whistle Noise Coming from Dash - kw 5.7 core heater IP IPC LS6

The following diagnosis might be helpful if the vehicle exhibits the described symptoms in the PI.

Hoot, whine, whistle noise coming from dash

To duplicate the noise the vehicle has to be between approximately 174 Degrees F and 200 Degrees F, while running the engine between 2200 rpm and 3000 rpm. The noise will readily duplicate while driving and in the shop (as long as the temperature is in the range indicated above) revving the engine. Engine cooling system pulsations are exciting the inlet and outlet tubes of the heater core and causing an audible hoot noise in the center dash area. One can attach chassis ears to the lower heater core tube on the right side of the center console, and use the Tech 2 to command the cooling fans on and cool the motor to below 200 degrees F. Run the engine up to 2200 or more and you should hear the noise quite readily in the chassis ears while sitting in the garage. Engineering is currently working on a fix.

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Please follow this diagnosis 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. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

(2004-05 Cadillac CTS-V)

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