Mitsumark

99 Vette..Driving normal at slow speed and started hearing a loud knocking sound..Does it in gear or neutral..Popped the hood and the sound is very loud..Coming from the area midway down the front of the engine..I happen to see some sparks coming from behind the area of the large pulley and tensioner area..Its not throwing belts yet and everything is normal as far as oil pressure,temp,volts,,ect..Car also has a fairly new GM balancer with pin kit..I dont see any wobbles anywhere..So I have loud noise and sparks..I know Im gonna have to dig in but looking for possible clues..Car has 62K on it...Thanks..

jim993

Remove the main belt and check the water pump, other accessories by hand. A water pump or other accessory bearing can make quite a lot of noise when going out.

If that doesn't find it, the AC belt is next.

Mitsumark

Gonna do that tomorrow..Ran out of daylight...I'm really leaning towards a bad WP..