92 Buick Century engine noise problem

I have a 92 Buick Century with a 3.3L V6 and recently a loud rattling noise (more like a bearing) is coming from the car when it is at a low rpm. When the rpm is increased it quiets down. I have replaced the tensioner assembly and pulley and water pump. The alternator spins fine (no noise by hand) and the power steering pump and AC compressor sound fine also. If I remove the serpintine belt it goes a way. What have I missed?

Thanks in advance for any help!

Bob Dehn Unplug your alternator while the car is running.

Let me know if the sound goes away. sounds like a bad balancer pulley(the very bottom pulley).it is a common failure for your symtom GM_Mech_319 wrote:Unplug your alternator while the car is running.

Let me know if the sound goes away.


Are you thinking that the alternator is bad? I don't hear any noise coming from it other that the typical whirring..... p.hinds wrote:sounds like a bad balancer pulley(the very bottom pulley).it is a common failure for your symtom


Is it possible for this to go bad? I thought it was a solid piece. I did notice that the some of the rubber appears to be peeling away though. I don't have an air impact to remove the retaining bolt. Do you think an electric impact wrench will have enough punch to break it free? yes it will go bad and I dont believe an electric impact will remove,but couldnt hurt to try. It was the harmonic balancer after all. In my 20 years of working on vehicles it was the first one I had to replace. I did decide to try the electric impact (240 ft of torque / 2400 bps) and it worked. Thanks to all for their advice.

Bob Dehn glad it worked out and thanks for the reply