Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › Honda Civic Temp gauge fluctuating, not heating well › Reply To: Honda Civic Temp gauge fluctuating, not heating well
First I would remove and test the thermostat to make sure it is operating correctly.
Next I would inspect and test the temp sending unit, also the connections.
Then vacuum fill the cooling system to ensure there is no air entrapment.
Then test the system.
Measure the coolant temp not by the dashboard gauge.
Might look at something like this: