hi. what would cause the radiator fan to stop working? while driving to work today the temperature gauge on the dash went all the way to the hot side.(the red) the car has plenty of coolant in it and i have noticed no leaks. later in the day i started the car and noticed the fan wasnt turning. i have had slight problems int the past with the temp. going up while the car is sitting still, idling, but nothing like today. any ideas?

In most cases the fan is working just fine, however the sensor is either not functioning properly to signal the fan to turn on, or there is blockage preventing the sensor from doing anything at all.

Turn on your A/C and see if the fan comes on. If not, check the fan relays or connect the fan directly to a power source to check the motor.

Most likely it will turn on, in which case you will check for blockage. When the engine is cool, feel for pressure at the upper radiator hose. There should be no pressure and the hose should not be warm (since you just started the car). Continue checking for pressure as the car warms up. When it reaches operating temperature the thermostat should open and the hose should warm up as pressure builds. If no pressure builds,the thermostat is likely stuck. It could also be a bad water pump, but less likely.

If pressure does build up and the hose gets warm, you may have blockage somewhere else.

All that said, when you are driving, this engine should not really get too hot. The air flow just from moving down the road will keep it at a reasonable level. However, if you are stop and go in city traffic it would likely heat up. At any rate, base on what you have said I would first suspect radiator blockage, especially based on the age of the car and the fact that most people never change their coolant.

You should be able to get a new radiator for about $100 if it becomes necessary and it is simple enough to do yourself. Just do some troubleshooting to see if coolant is flowing as it should.

MM22, since you mentioned sensors, but didn't say what to do with them, I'll pick up that. The main one that affects the fan is called the engine coolant temp sensor (ECT). It sends a signal to the engine computer (EEC) indicating the temperature of the engine coolant. In turn, the EEC will turn on and off the fan based on the temp. You can trick the EEC to turn on the fan by pulling the two wire connector off the ECT while the engine is running. If wrong, someone will correct me, but I believe on the 1.9, the ECT is screwed into a pipe that has several connections that connects to the thermostat housing and goes to the heater hose. The pipe and ECT are behind the upper radiator hose. Not sure about the 1.8, but I would guess it either has a similiar setup or the ECT is screwed into the intake manifold or head near the tstat, heater hose, radiator hose vacinity.

thanks very much for the info. mm22 i ran through your tests you gave me today. very helpful. the fan does work. i may have looked at fan prematurely last time. the top hose has pressure and gets warm when engine temp comes up. this tells us that the thermostat and water pump work, correct? then what the heck could it be that makes the temp gauge go all the way to the red area? could it still be a blockage? how do i check for that? could the temp gauge be broken? i am perplexed. please help. thank you very much.

A couple things... since the upper hose gets pressure and warms up we know that the pump and thermostat seem to be working. The only other options I can think of off the top of my head are that there is blockage in the radiator preventing the coolant from circulating, or the sensor is not signaling the fan to turn on when it is supposed to... or both.

I still suspect blockage as your primary problem, and a check of the lower radiator hose might give the info you need. When the upper hose is hot and pressurized, what do you feel at the lower hose? Any circulation? Cold and squishy? If you can get your hand in there to touch the fins of the radiator (carefully, and don't burn yourself), you should be able to detect a circulation problem by feeling for a cold spot.If it is hot up top and cold down below... you found your problem.

I think you might also need a new sensor.... perhaps the overheating killed it? I am not sure how much they can take.

I think the sensor is bad. If the radiator was plugged the fan should still kick on.

No, it is not the sensor. The fan's relay is bad.

Two years ago my brother's Escort had the exact same problem, which was fixed by a new Relay.

Yes, it should come on, but the way it had been described it also sounds like blockage. This engine should not be red lining just because of the fan.

thanks all for answers. today i was limping the car home and the radiator blew right where the top hose connects to the radiator. the plastic of the radiator where the hose connects broke. what would have caused this? blockage? the car stayed cool for the first part of journey but then heated fast and blew.it looks like new radiator time but still might have original problem too.

Moose described the problem well. The blockage in the radiator caused a pressure build up which blew the tank off. A new radiator should be the fix for this. The fan on my Scort only operates when the A/C is on. The rest of the time the radiator handles the heat without the fan. My temp. gauge never goes up even in stop and go driving. Of course this is not to say that the fan is all right. I think the fan and the radiator are at fault.

In Florida both of our escorts get hot in stop and go but never while driving. And if the fan didn't come on with the A/C check the relay. My wifes went about a year ago. On the cover in the fuse panel in the engine compartment it wasn't listed as a fan relay which made it a pain.