prplglide

Hi again,

My 07 Civic coupe consistently has the cooling fans running, when the engine is running and not when it's off, even when the ambient temperature is below 32 Fahrenheit (0 Celsius).

Preliminary research has pointed me towards the cooling fan relay. However, the one I ordered is just a bit too big (Beck/Arnely # 203-0198).

Besides the main fuse box under the hood, is there a different location for the relay?

Could this issue be something other than the cooling fan relay?

The coolant has not been changed in several years, is this particular model Civic fussy about coolant age, in terms of performance?

Is there anything else I should be looking at, coolant temp sensor perhaps (engine temp gauge never gets above 1/2 way between cold and hot)?

Thanks for any advice provided.

oragex

When you start the car in the morning with a cold engine, does the fan start running right away?

prplglide

Depending upon the ambient temp (usually above 35 Fahrenheit or so) both fans will come on after a few minutes of the car running. If it's colder, it will take between 5-10 minutes before both fans kick in.

ezone

If you had a stuck fan relay, your fan(s) would continue to run after the car is shut off, and tapping on the offending relay would usually get it to let go and turn the fan off.

You indicate the fans begin running when you start the car, so.....
When this is happening, is the AC compressor also running? (clutch engaged)

Determine this before just tossing relays at anything.

If you have any defroster position selected on the HVAC panel, it WILL run the AC and the fans accordingly as temperatures and pressures allow. This is normal (unless you have the system turned off, that wouldn't be correct operation)

oragex

I would inspect first the thermostat in case it got stuck in closed position. 3-5 minutes should be enough to warm the coolant and that's when the thermostat should start opening. It appears it's not opening causing the coolant to get too hot and triggering the radiator fans.

I would rather not drive the car before fixing the issue. Head gasket on a Civic may fail easily when the engine overheats which can happen even when the temperature needle sits near 12h.

As for the coolant itself it is wise to have it replaced say every 5 years and by the same occasion to get a water hose and rinse well the radiator and the heater core (have the cabin heat switch at maximum before shutting off the engine).