2002 Silverado 2500HD 6.0L, Noise with AC selected "on" sounds like fan rub

Last post on Sep 27, 2009 at 6:55 PM

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#1 of 1 2002 Silverado 2500HD 6.0L, Noise with AC selected "on" sounds like fan rub by lost1z Sep 27, 2009 (6:55 pm)
I am confused, with max AC selected on, I hear what sounds like the fan rubbing during heavy acceleration and just coming off the acceleration. Fan tips seem to be worn, but good clearance around fan shroud. I do not winess any severe engine movement during acceleration or deceleration. Noise will occur in "park" or when driving. Water pump changed last year, everything apears normal. Belt tension & wear normal. AC blows cold. I was thinking of the following possible causes: broken motor mount (don't see motor sway), fan clutch, ac compressor, or harmoinic balancer. It is difficult to confirm with engine rpm around 2500-2900 rpm on quick accel or decel. Has anyone seen this before or have any input?

#1 of 1: 2002 Silverado 2500HD 6.0L, Noise with AC selected "on" sounds like fan rub by lost1z; Sep 27, 2009 (6:55 pm)

I am confused, with max AC selected on, I hear what sounds like the fan rubbing during heavy acceleration and just coming off the acceleration. Fan tips seem to be worn, but good clearance around fan shroud. I do not winess any severe engine movement during acceleration or deceleration. Noise will occur in "park" or when driving. Water pump changed last year, everything apears normal. Belt tension & wear normal. AC blows cold. I was thinking of the following possible causes: broken motor mount (don't see motor sway), fan clutch, ac compressor, or harmoinic balancer. It is difficult to confirm with engine rpm around 2500-2900 rpm on quick accel or decel.

Has anyone seen this before or have any input?