Hey there. I own a 2002 Ford Fiesta, and something very strange happened to me.
i was checking my engine and looked under the hood. the engine was running for 20 minutes or so, and it got warm, and when i looked on the dashboard, the thermometer was in the middle. at this time i expected that the radiator fan will kick in to cool the engine, but it didnt. instead the fluid reservoir started steaming up and two minutes later in overflow and the engine coolant fluid spilled out. If the fluid started overflow it means it got too hot, so i think the radiator fan should have kick in?? wasnt it??

The does work there is nothing wrong with the fan itself. because when i turn the Air Condition on, the fan immediately kicks in!! but only if i turn the A\C on.
It wont do it on his own like it should.

Anyone have any ideas about what could have gone wrong?!

 

Depending on if the coolant sensor is sending the right info to the PCM or coolant switch isn't working properly the fan could fail to come on. Not sure which set-up your vehicle uses, hopefully it involves one of those controls. Has the thermostat been checked?

 

First off, just for talking, was there too much coolant in the reservoir when stone cold? That would force the coolant expanded with heat to spew out of the reservoir.

There is a max hot and a minimum cold line embossed into the plastic overflow tank.

Otherwise I go with what hanky says.

skip.

 

so, about the thermostat, I bought a new one 10 months ago, so i guess there is nothing wrong with it. The fluid level when stone cold, was OK. Just inside the range it should be...

I was thinking about checking the fuses, but it dont know exactly where are the fuses of the radiator fan...

 

In the owner's manual there should be information as to which relay controls the cooling fans. I believe the same relay is energized either by the coolant fan switch and A/C request switch. It is possible the relay is getting tired or intermittent. The engine usually has to get to the area of 200+ degrees F before the fans come on. Anything that will lower the pressure in the cooling system like defective rad cap ,low anti-freeze concentration will allow it to almost boil.

 

ok Thank you very much. i will try checking some things in the car...