Sunbird running hot after replacing thermostat

I have a 92’ Pontiac Sunbird. I was away from home and some family members were driving it. It was reported to me that it was running hot. When I returned, I replaced the thermostat, it continues to run hot, with no heat blowing in the car. What could be the problem?

The problem might be with a blown head gasket.


Failed water pump (very rare) blown head gasket, (coolant is constantly going into overflow tank) failed electric cooling fan…fan should come on when gauge reads 'hot" or ANYTIME the A/C is on…

Thanks Tester and Caddyman. I’ll have to look into these suggestions a little more.

Could be air trapped in the system.
Is there a bleed screw?