97 civic hatch D16

the car overheats very quickly. it will go from being completley cold to over heated in less than 5 minutes.

there are no leaks in the system and it holds pressure.
the thermostat and radiator have both been replaced.
the coolant level is fine and rad. fan works.
the car is not throwing a CEL.

what else could cause it to overheat so quickly.

 

headgasket

 

that was what I was thinking. the only thing is that no smoke of anykind comes out of the exhaust. I checked for oil in the radiator and there was a small amount indicating that the head gasket is likely blown.
thanks