The temperature gauge is working like before, standing on 90 normally but not warm enough from heater, even on high
My car has 151000 miles.
My car has a manual transmission.
Hi, thanks for writing in. The temperature of your heater is going to depend on the circulation of the coolant, temperature of the engine, and the associated parts working correctly. The blend door actuators, level of coolant in the system, heater control valves, and driver controls must all be working correctly. You will want to start by inspecting the thermostat and make sure it is working correctly. If it is allowing too much coolant into the system, the heat from the engine used to heat the air for your heater will be decreased. Some sensors will trip a diagnostic troubleshooting code that can be seen when doing a scan. You may want to start there. Further testing of the system is needed. If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect this heater issue for you, and make or suggest any repairs as needed.