1991 GST doesnt warm up

[glassware]

I have a 1991 GST, when I crank the car up and let it sit for awhile it doesnt warm up? I was think a blown head gasket. When I drive the car it starts to overheat anyone know what the problem can be?

 

[Rob10_99]

"not warming up" could be because there is no coolant touching the thermostat.
If your low on coolant, even a little, it wont read correctly, either steam or boiling water could be giving you a false reading.

 

[illeffekt vr-4]

Thermostat stuck open?

 

[glassware]

Yeah I was thinking blown headgasket mostly, I check the thermosat to see if that could be problem. Are there anything else I can check that may cause this problem.

 

[1992awdlaser]

Every car warms up after sitting at idle. My car and truck do it in below 0 weather almost every year. If the coolant temperature sensors are good and the wiring going to them are good the only way the gauge won't go up is due to lack of coolant. Bad head gasket won't cause a car to not warm up. So chack: Lack of coolant, coolant temperature sensor for the gauge, and the wiring for that coolant temperature sensor.

Or are you talking about the heat not working?

 

[Defiant]

Your thermostat has failed partway open. It's not opening enough to cool at speed, and is open too far to let it warm up at idle. Replace. Do the cap at the same time.