tenelson

My girlfriend has a 94 Honda Civic DX. Lately it has been overheating. It does fine on the freeway, then as soon as you enter stop and go traffic, the temperature starts climbing rapidly. From what I've read, that sounds like a typical radiator fan problem.

I checked to make sure the fan was operating by shorting the connector that goes to the cooling fan switch. The fan comes on and does not make any unusual noise. So I replaced the cooling fan switch that sits in the thermostat housing.

I figured everything was ok, but I witnessed it overheating again yesterday. We quickly pulled over, and I popped the hood. With the speedo cluster temperature gauge at 3/4, the fan was not on!

We let the car cool down, drove it home. Again, the temperature started climbing once we were in stop and go traffic. When we parked it in the driveway with the temperature over 3/4, we popped the hood and found that the fan was on this time. As the car sat in the driveway, the temperature started going down.

Is it possible for a radiator fan to be intermittent? What could cause this?

The car has a new water pump (the old one was dripping), new thermostat, new radiator cap, and the new cooling fan switch.

a94civicex

On the fuse panel inside the car there is a 7.5amp fuse. Check this fuse becauseit runs alot. If it's bad it will not turn your ac on, lower windows if you have power windows & will not kick the cooling fan on. Check the fuse because I made the mistake by not replacing the fuse & it did this.

Si GUY99

New thermostat you put in or was told it was new? If it's new we'll rule that out for now, also get some antifreeze and when the car is cold (or been sitting for a few hrs after driving ) top off the radiator you may have air in there or a poss leak somewhere.

d16y8turbo

Try the following:

New radiator cap and thermostat.

Hook a garden hose to the upper coolant hose going into the front of the engine, detaching the lower hose so that the water can flow though. You also need to make sure the thermostat is out but the housing is on, and the heat in the car is set to full (don't turn the car on, obviously). Let the hose run for a good 5 minutes to clear out any gunk that might be in the engine.

Make sure the radiator fan is blowing air INTO the engine, not away. Also, if the fan is aftermarket it is probably not as efficient as the stocker.

When you replace the coolant make sure you follow the mixing directions to the "t".

Follow the directions for filling the coolant so that you dont have bubbles in the system.

If this doesn't work then the water pump is probably bad.

dpetro1

sounds like there may be some air in the system causing the fan to not operate properly. bleed the coolant and report back. also there is a cooling fan relay by the battery. might want to check that as well

Cynical 1

fan itself could be going bad. loose wire or connector somewhere? bad relay or fuse connections? air in system?

Gsr-teg23

yes sounds like air in the system. there is a bleeder valve on the engine side of the upper raidiator hose its a 12mm start the car let it warm up then open the valve untill the water starts to trickle out close it put water in the raidiator repeat untill water is full and thremostat is open and water is flowing

tenelson

Air in the system makes a lot of sense. I bled the system according to these instructions and the car has yet to overheat again. I'm expecting she'll take it on a longer drive this weekend, which is where the problem usually manifested itself.