[joedoh]

every time i fill one up from slap empty it needs a temp spike to get rid of any air pockets. if you notice bubbles coming from the tube on the rad, you might have air in the system.

the way to get rid of air in a cooling system when you have an expansion tank and a two way rad cap is to put some 50/50 in the expansion tank, warm the engine to operating temp, then shut it off and wait. the air will be forced out while running and then the radiator will reverse pressure as it cools back down (not running) and will draw coolant from the tank. if you dont have a tank hooked up, it will just draw air back in and you will need to start all over.

otherwise, make sure the thermostat is opening. feel the upper and lower hoses, if one is hot and the other is cold and the engine is warmed up, the thermostat may not be opening.