belt noise

[chris989]

Hello All,

V2500 5.7.

I installed an onboard air system from littleshopmfg. It is a york 210. Prior to the install my engine/belt system was as expected. The ac would kick on and the usual noise would accompany it.

Now, with the second pump and a longer belt I get a horrible hum/vibration somewhere when the OE AC comes on. I can not see or hear anything under the hood but when in the cab it is that low rumble and resonates. Like when you can hear a subwoofer from a car 50ft away at a stop light.

Any ideas? Belt to tight? too loose? The tensioner feels right

https://www.littleshopmfg.com/gm-4-3...ompressor-kit/