A thermal switch is installed in the right radiator tank, which turns on the engine cooling system fan if the coolant flowing through this tank has a temperature higher than the required one. It also turns off the fan if the coolant temperature drops below a certain value. At the switch-on temperature, the contact in the thermal relay closes the electric circuit of the engine cooling system fan, and it starts working.
Be careful when working in the engine compartment: when the ignition is off and the engine is hot, the fan may turn on by itself. Therefore, when the engine is hot, do not put your hands in the area where the engine cooling system fan is operating!
Note: Recommendation: in order to check whether the engine cooling fan will actually start working on a hot engine, you need to do the following: with the engine already warmed up and idling, watch the coolant temperature readings. The fan should turn on before the instrument needle (depending on modification) enters the shaded area. The overheating indicator lamp should not light up, otherwise there is a high probability that the thermal relay is faulty.
Engine cooling system fan malfunctions
A faulty engine cooling fan can cause the coolant temperature to become too high; this happens when the engine is idling for a long time or when driving in the mountains.
A faulty fan doesn't mean your ride is over:
- After the engine has cooled down, you can drive to the nearest auto repair shop at medium engine speed and a constant, fairly high speed. At the same time, monitor the coolant temperature and the overheating indicator lamp.
- Idling and slow driving in this case are dangerous for the engine, since not enough air passes through the radiator fins for cooling.
Troubleshooting
1. Disconnect the dual plug of the thermal relay.
2. Connect both contacts in one of the halves of the double plug with wire.
3. If the fan starts working, then the thermal relay is faulty.
4. To continue the trip, securely fasten the previously inserted piece of wire that closes the contacts.
5. To prevent loose wire from dangling and to avoid short circuit, wrap the double plug connector with adhesive tape.
Removal the engine cooling fan
The C-type engine, and some F-type engines, have a free-running fan, with its motor riveted to the fan holder (2). The fan holder is screwed to the left and right radiator tanks (1).
A more powerful diesel or 16-valve engine fan has a higher quality flat motor that rotates the fan impeller in the air duct.
1. Disconnect the terminal of the battery from the battery and disconnect the plug connection of the wire of the thermal relay and the engine cooling fan.
2. Disconnect the wire from the fan mount holder.
3. To remove, unscrew the two fan motor mounting bolts.
4. Remove the fan motor and holder from the radiator.
5. If the fan motor is riveted to the bracket, drill out the rivets.
6. Fix the fan pulley and unscrew the central nut.
Attention! Attention: left-hand thread!
7. Remove the fan pulley.
8. When installing, use bolts instead of rivets to connect the fan motor to the holder, and treat them with an anti-loosening agent.
One way to determine the fault, if there is a suspicion of the fan motor, then disconnect the plug connection (2) of the thermal relay on the radiator and short-circuit both sockets of the plug with wire or a paper clip. The fan should work.
The 16-valve engine is equipped with an additional electric coolant pump (shown by arrow) in the cooling system, which after the ignition is turned off continues to circulate the coolant through the cooling system for about 5 minutes. On an overheated engine, the engine cooling system fan also turns on.