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
To test a hot water heater thermostat, you can use a multimeter to check for continuity in the thermostat. First, turn off the power to the water heater. Then, remove the access panel to expose the thermostat. Use the multimeter to test the thermostat's terminals for continuity. If there is no continuity, the thermostat may be faulty and needs to be replaced.
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.
To test the thermostat on an electric water heater, you can use a multimeter to check for continuity and proper functioning. First, turn off the power to the water heater. Then, remove the access panel to expose the thermostat. Use the multimeter to test the thermostat's terminals for continuity. If there is no continuity, the thermostat may be faulty and need to 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