car making buzzing & whining sounds?

[Mike]

My car, a 2005 Pontiac Grand Prix 3.8L V6, started to make a weird buzzing sound after driving it through the snow in December. The sound only appears around 1500-2000 RPM and is loudest when the car is still cold, lessening as it warms up. It also sounds like it's coming from underneath the car and not the engine compartment. It didn't seem like anything major, so I didn't do anything about it, thinking something was just loose.

But today I started my car and began driving. Suddenly I start hearing this whining sound coming from my car when accelerating. The whining would get louder as I accelerated, but when the gears shifted, the whining "whined down" a little only to get louder as I approached the next gear. However, there was no sound when cruising or idling. After looking under the hood and revving the engine a few times, a friend and I discovered that the sound was coming from the area near the belt (passenger side). Oddly enough it disappeared after the car warmed up.

I did some research to find out what the problem was. Possible problems ranged from belt issues to the transmission. The transmission however is still shifting normally and seems to be functioning properly.

Any ideas? Thank you.

 

[Ben]

Off the top of my head i would guess that the weird buzzing from underneath is some part of the exhaust system rattling(loose heat shield or loose clamp) possibly jarred loose during the snow driving. The second noise sounds like you are low on power steering fluid and the p/s pump is whining. Tap on or jiggle the tail pipe and listen for the noise and fill your power steering fluid up and see if the noise is gone. Both noises most likely not a big deal. Good luck.

 

[Mike]

You need a new serpentine belt, and check for damage on any of the pulleys. Also check to see if the noise is coming from the alternator. GM vehicles are known to have short alternator lives, and this could be the clue that it's on its way out.

 

[theman]

check the belt