Noise when turck is at idle

Due to start of noise and after inspection of harmonic balancer. I have changed harmonic balancer out due to the center partly blown out of it. Hoping that was all the noise was but still makes noise I also am waiting on belt tension-er to come in due to fact its bouncing all over the place on truck. I have also ordered idler due to bearing being dry sounding. With belt on truck sounds like crap at idle but give it some pedal and it goes away. If you take the belt off all together and start the truck at idle it doesn't even make the sound is the any thing else it could be that I might be missing pleases help thank you