Pontiac Repair: Overheats, temp gauge, train noise

Question
QUESTION: I have a 97 GM 2.4L Quad 4 motor and i recently just rebuilt portions of the motor.  New water pump was also installed.  i ran the motor for the first time last night and the engine almost overheated. luckily i shut it off before it got that far.  i installed the thermostat with the spring facing the block.  Refilled the radiator with new antifreeze.  when the heater is on that car will not get that hot but as soon as the heater is shut off it gets hot quick.  What is the possible cause for this?  

Another question - same engine - i have extremely loud valve train noise.  i turned the engine over by hand and when the valves close shut is when it is heard.  is there anything i can do to alleviate this without removing the cam box? what would be my best course of action?  i have extra cam boxes that came off another GM 2.4L.  Casting numbers are the same are they interchangeable with out causing damage to the head/valves?

ANSWER: Hey Jeff:

That engine is extremly hard to bleed the air out of due to the radiator being lower than the engine and the position of the thermostat. just keep running it and feather the gas up and down even tually it will burp out the air just keep an eye on the temp gauge.

As for the noise first off make sure you have good oil pressure if so then you have a lifter or lifters that are bad It may not be the cam carriers but if you take them off and they look scored up where the lifters go or if any of the lifters seem to fit loosly in the bores swap out the carrier.
good luck :)


---------- FOLLOW-UP ----------

QUESTION: Thank you, other cams in no more noise!!! quiet except for exhaust leak:( (need to weld  the exhaust) Anyhow my cooling fan is now not turning on at operating temprature. the check engine light is now on.  It was not on when i started it last night but when i started it today after work the light came on and that is when i noticed the fan not working.  Could this cause the light to come on or is there another issue?

Answer
Hi Jeff:

Yes the light could be on for the fan control circuit. or it could be one because the engine overheated at one time. with out knowing what the code is that turned the light on I can't tell you for sure.. those older cars had what was called quad drivers basically they are self resetting solid state relays in the computer if the computer if going to turn on the fan relay and it doesn't see what it's looking for it turns off that driver and turns the light on..