I thought it was the water pump making noise but when I removed the fan belt cover the noise went away, I think the alternator may have been slightly rattling against it. I pulled the water pump off and it looks decent, the bearing seems fine and the impeller looks good to me but please see below. I found a slight bit more pitting from electrolysis thought. I also noticed that when I turn my cab heater on the temp gauge drops down about an eighth of an inch immediately, could that be caused by a ground issue?