any help here would be appreciated because i dont know whats going on, but heres the scoop.
the last two times i have driven my car it has been cold and i have needed heat, the gauge will quickly climb to 220 then drop back to a cooler temp, all the while no hot air, then the gauge will go back to 220(normal operating temp) and finally put out hot air. Up till now you would think bad sender on the gauge, right? But heres where it worries my, i will keep driving (driving, not sitting in traffic) and the temp will rise to 240 to 260 on the gauge and well doing so, the hot vent air turns to cold. There has been no boilover, my mixture is 60/40, air damn in place and no leakage to indicate a bad pump, but i will check again today anyway, any ideas? thanx.

 

Try swapping in a new thermostat.. may be slipping.
Maybe also check the belt tightness too.

 

Yeah, sounds like a thermostat or possibly even air in the system.

Good luck and keep us informed.

 

yeah try the cheaper things first