engine makes whining sound when first running. on 2004 Pontiac Grand Prix GTP

After the car warms up a while, it seems to stop. It only makes the noise when the car is in motion. It does not change with turns or brake application

by in Braidwood, IL on December 01, 2011
1 answer 1 comment
ANSWER by on December 01, 2011
It could be many things, unfortunately and without hearing the noise first hand or being able to do some basic diagnostic tests or be able to drive the car, its hard to say what the source of the noise may be. Look at the fan belt make sure it is tensioned OK, if that engine has a harmonic balance pulley that has a bonded rubber ring between the pulley and the fan belt hub I have seen them fail on some engines. Does the noise occur when the transmission is put in drive with your foot on the brake ie the engine torqued under load?
COMMENT by on December 02, 2011
Thanks for your reply. I will check those items. It does it when the car is parked and when I am stopped at a light (and still in drive). It does get louder with acceleration. Turning does not change it either (I thought maybe power steering). I have not noticed any decrease in any power or electrical systems in the car. I was wondering if it could be the supercharger? The sound diminishes after the car has been driven awhile (1/2 hour or so). Thanks again for your input!!