I don't think its a head gasket...maybe water pump related.
Have you ever replaced the water pump? You could have a broken fin from your pump lodged somewhere.Do you have any antifreeze in your engine oil?? Can you smell antifreeze from the exhaust? Are you loosing any antifreeze? (Burning it)? Does the car smoke bad when you first start it??You could also have a bad air lock in the system...That will cause it to overheat. Run the car for awhile with the filler cap off and look for air bubbles when the thermostat opens.You may have to run it on a bit of a fast idle to get the thermostat to open.
