Weird noise

I get a weird noise when driving. It happens at different speeds, it sounds like sticking something into very edge of a fan its like a metal on metal almost not grinding but happens frequently.

no shudders, ride is smooth no jerks or nothing.

any ideas?

96 buick park avenue 3800 series II

WE NEED MORE INFO:popcorn:
Do you have any idea what part of the car the noise is coming from? Is the heater fan running when you here the noise? Is the noise coming from the engine/trans area? Have you had any transmission work done lately? If so, pull the dust shield on the bottom of the transmission and inspect the torque converter bolts for tightness. :sunglasse

i cant pinpoint it further than its coming from under the hood. doesent happen if i rev engine in park only when im driving. i dont know about heater fan will check next time i drive it.

no transmission work done while ive owned the vechicle.

Harmonic Balancer would be my first guess from the way you describe your problem. Alternator and water pump (and any other moving bit of machinery on or in the engine) could do it also.

I know from experience that the sound from a bad harmonic balancer is very hard to isolate and identify. Some times you can see physical damage to the outside of the HB caused from wear/tear.

how would i go aboust diagnosing a bad harmonic balancer?

The balancer is made up of an inner hub and an outer hub, separated by a rubber insulator ring.. Look for, visible cracks or warps on the balancer, wobbling pulleys when the engine is running, or improperly timed/running engines due to slipped outer ring. If you place both hands on the outer hub and you can rock it back and forth, (clockwise- counterclockwise) it is time to replace it!:crying:

Unfortunately I had to figure it out by the process of elimination. But hotz28 suggestion sounds like a better way.

how would i go aboust diagnosing a bad harmonic balancer?

ok where exactly is the harmonic balancer. I know its on serpintine belt somewhere and on passenger side of motor but then i dont know which one it is.

3800 series 2 park av

The big guy on the very bottom attached to the crankeshaft :thumbsup:

Here is a picture of one off the engine.
http://img292.imageshack.us/img292/304/bal309406b1sk4.jpg

i took it to a mechanic to listen to it. he drove it and listened and said he thought it was a heat shield coming loose in the exhaust system making the noise. ever heard of that?

i didnt have anything fixed yet

Certainly easy enough to confirm, the shield is too close to the exhaust for whatever reason. It's normally more pronounced at light throttle.