Table of contents: Viscous fan malfunctions ↓ Viscous fan malfunction ↓
If the thermostat fails or the V-belt breaks (only with a four-cylinder engine), a non-working radiator fan can cause the coolant temperature to rise too high.
After the engine has cooled down a bit, you can drive to the nearest workshop at medium speed and smoothly. At the same time, do not lose sight of the temperature indicator and the warning light.
On the contrary, idling and creeping speed are fatal for the engine. Under these conditions, the cooling flow of fresh air does not pass through the radiator fins. If the continuation of the trip is only possible at low speed due to driving conditions, then you must immediately find out the cause of the malfunction and, if there is an electric fan, put a jumper on the thermal switch if necessary.
Viscous fan malfunctions
The viscous clutch should be replaced if:
- when the engine is not running, the fan does not turn easily;
- the fan has a large axial and radial runout (a small gap is acceptable);
- silicone oil comes out of the viscous coupling.
Viscous fan malfunction
1. First check the additional fuses (see chapter Electrical equipment).
2. If they are OK, then disconnect the thermal switch connector.
3. Short-circuit both contacts in the wire connector with a piece of wire.
4. Short-circuit all three connectors in the two-stage thermal switch.
5. If the fan now works when the ignition is on, then (in this case empirically) a faulty thermal switch removed from the electrical circuit is a common malfunction.
6. To continue driving, clamp the jumper wire into the connector and securely insulate with tape or adhesive tape to prevent short circuit.
7. If bypassing the thermal switch does not help, check the fan relay in the central switching unit (see chapter Electrical equipment). If both wires of the thermal switch are shorted, then you should be able to hear the switching contacts in the relay closing when the ignition is turned on.
8. If this is not the case, then a temporary jumper is made in the relay. To do this, connect the contacts of the relay connector terminals 30 and 87 with a piece of wire (with a paper clip) and insert the relay.
9. The radiator fan should work even when the ignition is off. If so, the relay is faulty.
10. A jumper made from wire can be used as a temporary aid on the road. After the trip it should be removed.
11. If success is not achieved in this way, then check the fan motor:
12. Disconnect the wire connector to the fan motor and connect the jumper wire to the positive battery terminal in its place on the red/black wire connector. The brown wire connector connection goes directly to the negative terminal.
13. If the propeller still does not rotate, the fan motor is faulty - replace it.
14. But if the fan is working, then the relays should be checked (see chapter Electrical equipment), wire connectors, as well as all connections of the thermal switch and electric fan.
15. You can also continue your ride without any worries with the radiator fan powered directly by the battery. The auxiliary wire must be insulated to prevent short circuits.
[The article was copied from the website «AudiManual»]