Hello again. I have a '95 CX hatchback and my radiator fan has never worked since I bought the car. I replaced my head gasket just after christmas because I was leaking oil externally and had oil in the coolant. When doing this I also replaced the thermostat. Upon filling and bleeding the coolant I noticed that the fan never came on. Also my temp gauge in car never makes it higher then a quarter so I though my thermostat had failed open. No such luck there. I'm still driving the car because it's -10C here and I don't think there is a real danger of overheating as I'm not in stop and go traffic. The other thing I don't understand is my upper hose is hot and my lower is stone cold. I don't think my rad is clogged becuase it drained well enough and I'm not using coolant. I'm going to jump the plug for the thermoswitch to see if the fan will kick on. What pins/plugs do I need to jump on the fuse box to run it without the relay to see if that's the issue? Any other suggestions?

Thanks!

 

The fan is actuated by temperature in the lower hose. In cold weather the radiator may lose enough heat naturally that the fan is not necessary even with the car sitting still.

The fuse and the relay are in the box next to the battery. Check the fuse first of course. If the fan doesn't start with the switch jumped and the key on, test for voltage at the fan wires. Power to the fan but it doesn't run means the motor is bad. If no voltage at the fan, test the relay by swapping it with one of the other ones in the box. There are 3 in there that are all the same type of relay.

The engine may be properly warmed up even though the gauge doesn't show it. Does the heater make hot air? It's also possible your new thermostat is no good. You should be using a 195 degree one. If you unplug the wire from the gauge sender (sensor with one wire screwed into the head under the distributor) and ground it, gauge should go all the way up to hot when you turn the key on. If the gauge does that OK, try a new sender.

 

it may be the radiator switch too its located by the thermostat i believe

 

Thanks for the reply guys. Well here's the update. I do get heat and lots of it and my aftermarket stat is a 195 which I installed correctly. I checked the 15A fuse in the box and tested the relay by swapping it with the defroster one and that works. I also disconnected the thermo switch and bridged the connector with a piece of wire and the fan works. So assuming the stat is good I'm going to replace the thermo switch and re-bleed the coolant. Can I replace the thermo switch without draining the all the coolant and just re-bleed? I also grounded out the wire for the sender for the gauge and the gauge looks good but the sender is bad. I'll probably replace that in the spring.

 

Yes you can replace the thermo switch without draining. Make sure engine is cold, open radiator cap to release any pressure then put it back on, unscrew switch and slap the new one in before much coolant can run out. The gauge sender is the same way.

 

my temp never gets to the half way mark and the fan never turns on. its just fine, id leave it till summer then see if it turns on.

 

I just bought a 94 civic with 120,000 mi on it and I'm having problems with the cooling fans. My car overheats almost everytime I drive it. The headgasket is fine and everything just the cooling fans will never turn on and I can't find the solution, I live in las vegas so this is a big problem for me because the heat doesnt help.

 

Find the fan switch in the thermostat housing, which is where the lower radiator hose connects to the engine. Unplug the switch and put a jumper wire between the two wires in the plug. The fan should now come on immediately when you turn the key on.

If fan still does not run, troubleshoot the fan system -- fuse, motor and relay.

If it does, test drive with the fan on all the time and see if there is any overheating.
No overheating -- replace fan switch
Still overheats -- try a new thermostat. If the thermostat is stuck closed (and everything else OK) the engine will overheat yet the fan will not come on.

 

Also try bleeding the cooling system.