Hot Car

I replaced the switch and sensor for the radiator/cooling system. We let the car run in the driveway for about twenty minutes in this 100-degree weather and the radiator fan would turn on at the appropriate times. On the way home, I stopped at a light for about a minute and there wasn't a problem. At the second light, the temp started climbing. I pulled into a parking lot, popped the hood and found that the fan was NOT running.

I turned the car off, put the key in the ACC position and the fan came on and stayed on until the temp dropped to tolerable levels. When I got home, I sat in the driveway and the temp rose. When it got really high, the fan came on for 20 seconds and then shut off without doing much to cool the engine. I shut the car off, put it in ACC and it did the same thing that it did earlier: stayed on until the engine was within acceptable levels.

It almost sounds like a programming issue. Any ideas?

Former User

Bleed the cooling system. What car/engine?

Hot Car

2000 Civic LX.

How would bleeding the cooling system fix the fan's lack of activation?

Former User

It's something simple to try first. The ECT switch on the thermostat housing contacts coolant and measures its temperature. If an air bubble is trapped in the cooling system, it can prevent the ECT switch from reading coolant temperature.

Bleeding the cooling system may take 20-30 minutes.

1) Park the car on an inclined driveway with the front end higher than the rear.

2) Push/turn the dash heater lever/**** to MAX heat. Fan need not be on.

3) Follow the directions in the diagram below