Overheating Issue (Heater Related)-Searched

[ferrarilover7]

Recently my car has been overheating at random times. The overheating seems to be directly caused by my heater not working. The system will blow cold air when I have the heater on, and the car will start overheating. As soon as the heater kicks in (usually after I toggle the system on and off a few times) the temp guage goes back down to normal. Then the cycle usually starts again.
I am pretty sure my heater valve is broken. I have had that "thud" comming from it every three seconds, but recently the thud went away, which I'm guessing means it finally broke.
Would a broken heater valve cause overheating? If it is always closed (in my case, probably broken), would it prevent flow of coolant through the engine causing it to overheat?

Thanks for the help in advance.

[rootuddha]

when was the last time you replaced your thermostat

[dcroghan]

airbubbles in system, low on coolant, faulty aux. fan switch, themostat

Could be any. Trial and error my friend.
I am thinking it has nothing to do with the heater.

[ferrarilover7]

Thanks for the help.
I recently replaced the thermostat and waterpump so I'm pretty sure they are ok. I will rebleed the system and see if it goes away.