This weekend I was one a trip in my '98 Civic, and I noticed some movement in my temperature gauge. It didn’t really overheat; the needle never got near the red, but it did go a little higher than usual.
Normally, once the engine heats up, the needle on the temperature gauge doesn’t move, not even a little. It sits right under the squiggly lines on the temperature gauge icon. However, on Friday, when I got off the highway, the needle rose into the upper part of the icon, to the part with the thermometer.
As soon as the car started moving, the needle on the temperature gauge went back to its normal spot, so I assumed it was a problem with the radiator fan and I kept on driving, prepared to turn on the heat if the needle on the temperature gauge started going up.
Saturday morning I took the car to a local shop in Jacksonville, and it turns out the engine needed a new fan and a new thermostat.
The first lesson that comes to mind is that keeping an eye on my temp gauge might have saved me an engine. It certainly saved me a head gasket. Since a head gasket or new engine would have been worth more than the car, catching this before it became a problem saved me from having to buy another car.
The next lesson is that my Civic had two things wrong with the cooling system, and yet it barely showed any symptoms. It helps that the air conditioner doesn’t work I guess since a working A/C would probably have made it overheat. In any case, I’ve probably been driving without a working radiator fan for some time.
The final lesson is that if I had tried to diagnose this myself, I’d probably be driving around with a new radiator fan and a bad thermostat. I paid about $435 for a new fan, thermostat, and fresh coolant (I declined the cooling system flush) and it was worth every penny.