Temp gage not working

I have a '98 Honda Civic and recently the temperature gage stopped working properly.

If it is idling for a few minutes, the temperature gage will move up to the normal position. As soon as I start driving, it goes back down to cold. The heat temperature corresponds with what the temp gage says, even if I have been driving for a while and the engine is definitely warm.

I took it to the dealer for another issue and asked them to look into the temp gage and they told me it was just low on coolant and that it should be fine now. And I stupidly believed them. Argh!

My guess is that it is the thermostat? If so, is this something I could somewhat easily change myself?

Even though I should bring it back to the dealer on principle, I’d rather do it on my own and not have to deal with them again.


It appears by your discription of the problem that the thermostat is stuck open. You should see the temperature drop if you pick up speed on a freeway, and rise again at a stop light. It is not hard , but if you have not done it before, it can get messy. You will have to buy new coolant though, whether you do it of the shop does it.

Make sure the fan behind the radiator is working–that is, going on and off at times.

And or the water pump is worn, and or there is still air in the system. If it was low on coolant, watch that very closely for a while, you may have a leak.