My boyfriend just replaced my head gasket, we got the head shaved, all gaskets were replaced, spark plugs, wires, oil, oil filter, thermostat, coolant, and it started fine the first time we started it again and it sounded great! Then it started to over heat again so we replaced the water pump. When we started it again it sounded horrible, like a knocking noise, and the car still over heated with new water pump. Any ideas on what the noise may be and why it is still over heating with all of the things we just fixed? One of our friends said it may be because he tightened the head down to much?