Low coolant? Wrong thermostat temperature range? Heater core plugged,restricted or airbound? Water pump not circulating coolant? Temperature control cable not adjusted properly?
Try flushing heater core Try flushing heater core
yes if it stuck open.
How did you change the thermostat?
Check into the temperature control valve--this is different than the thermostat.
flush out heater hoses
The heater cor was replaced but it is still not getting warm
If a thermostat is not working properly, you cannot calibrate it. It must be replaced.
Thermostat probably needs to be replaced.
Was the gasket replaced? Have you checked the hose and the heater core. Is everything tightened down?
heater core plugged or air locked check to see if hoses going to heater core are hot
MY CAR WAS DOING THE SAME THING NO HOT AIR COMING OUT OF THE HEATER I CHANGED THE THERMOSTAT. IT WASNT THE THERMOSTAT. I GOT TO CHECKING AND THE SEAL IN THE WATER PUMP WAS BAD. I REPLACED THE WATER PUMP AND IT WORKS FINE NOW.
The heater valve could be failing to open for one reason or another.