I often drive my Civic an hour to where I work. I will get on the freeway and the car will do great during the drive to work but when I hit stop and go traffic really bad or get stopped a lot at stop lights after getting off the freeway the car heats up really fast and the temp gauge shoots up.

I figured this must be an issue with the fan not coming on at all or not coming soon enough. So I replaced the relay after not seeing on after one of my drives. The fan was on the next few times I checked. But still it continued with the same behavior so I replaced the thermostat and fan switch. The car still continues to get really hot so I am not sure where to go next.

I turned on the AC and my AC fan came on so both fans function. I am not sure if maybe I have a radiator problem or if my fan just isn't blowing hard enough, or if it is turning on at the right temperatures.

Any suggestions?

Should I look into replacing my Electric Fan Thermostat?

 

Hey Atholon,

Before proceeding with the replacement of your Electric Fan Thermostat, I would try "burping" the coolant system in order to see if your overheating issues are resolved. Air pockets can cause overheating because there will not be enough coolant in the cooling system, even if the radiator and coolant reservoir appear full. "Burping" the cooling system will allow these air pockets to escape. Here's how you would perform this procedure:

1) Add a mixture of one-half water and one-half antifreeze to the radiator. Fill it right up to the top.

2) Fill the overflow/coolant reservoir (pictured in this Civic cooling diagram) with the same 50/50 mixture.

3) Leave the radiator cap off, turn the engine on and let it run until the radiator "burps": You will see the coolant level drop and may see or hear a large air bubble come to the top as the system burps.

4) Keep an eye on the temperature gauge throughout this process.

5) Refill the radiator to the top and coolant reservoir as needed.

6) Put the radiator cap back on.

7) Note that if the engine runs hot after this procedure there may have been another pocket of air that "burped." Let the engine cool down and then add more coolant to both the radiator and the coolant reservoir.


Try performing this simple procedure and if your Civic is still overheating then report back to base and we can take another crack at resolving the matter

 

Didn't work very well on my drive last night

Guess I get to try the new thermostat?

 

Turn on your car, let it idle with radiator cap off until fan kicks on, then close cap, you done.

 

So you have confirmed that the fan comes on with the A/c and that the radiator fan comes on as needed (cycling on and off - without touching the A/c button)?

You can pull the thermostat out and drop it in a pot of boiling water in order to see it open. Once open, turn off the heat source and watch for it to close. If you are overheating, and the Tstat is the problem, it would stick closed.

Make sure you bleed the air out of the system properly by doing what techtalk and droopy said. Be sure to turn the heat on in order to cycle out any air bubbles in the heater core, too.

Otherwise, conduct a compression test to see if there is a possible head gasket failure.

 

Yeah just the ac fan comes on. I'll let it run without the cap on and turn on the heat. Then I'll try your idea so I don't waste $40 on a new thermostat.

Thanks for the idea.