stalkervette

I have a 96 e320 and after i installed the a/c pump and and brought it down to get the evac and recharge for the a/c I started hearing noise which sounds like the water pump. It only happens when i turn on the a/c and goes away when i shut off the a/c. Does the a/c on put more stress on the pump which i don't know about? Changing out the water pump is no problem which i'll end up doing myself. its like a clack clack clack clack sound. Don't want to really drive it around and have the water pump go out on me. Doesn't sound like the noise is really coming from the a/c pump which i did install the oil for it. It sounds more like its coming from the top of the by the water pump.

Lancelot

That clacking sound could be the compressor clutch. Did you get a used or refurbished compressor?!

stalkervette

the compressor is brand new. sounds like the noise is coming from the water pump. I touched the thermostat housing before it got too hot and can feel the noise in this area.