The engine «boils» — a faulty radiator fan

Your Focus's cooling system handles long idle runs and stressful mountain passes in equal measure. If, however, the temperature rises to the boiling point, then the cause may be «on strike» radiator fan. Do not immediately tow your car (see PCM superheating program): Let the engine cool down and drive slowly to the nearest workshop. While you should avoid idling and driving slowly in high gears whenever possible, your feigned caution unnecessarily heats up the engine - too little oncoming air flows through the radiator in this case.

Be careful: if a warm engine has just been turned off, never put your hands near the fan! The fan, even when the ignition is off, can suddenly start working.

First aid - close the thermal switch

Check the fan fuse first.

In the second step, disconnect the multi-pin connector from the thermal switch.

Close the contact that supplies voltage with the ground contact in the connector. So you exclude the thermal switch from the electrical circuit. If the fan turns on, the thermal switch is faulty. If it does not work, then either the conductivity in the supply wire is broken, or the fan itself is faulty.

Tighten the wire jumper well until final repair. And in order to prevent the pinched wire from falling under the fan blades, fix its end with adhesive tape in a suitable place.