Checking the radiator and fan housing (VW Golf 1)

The fan housing may be under voltage and thus electrolysis is caused. The test is carried out as follows:

Remove the wires from the thermal switch.

Connect a voltmeter between the fan housing and the negative terminal of the battery. If there is no reading on the device, it does not matter. Continue checking as described in the next section.

On the contrary, if you notice tension, this indicates that urgent repairs are needed. The radiator, together with the electric fan and the thermal switch, should be replaced.

Drained coolant should not be reused.

After installing new parts, fill with clean water (preferably distilled).

Warm up the engine and let it run.

Drain the water completely again.

Refill the cooling system (see section "Filling the cooling system", chapter "Cooling system").

Then the radiator and fan housing are checked: is there voltage?

To do this, connect the voltmeter to the negative terminal of the battery and connect the positive terminal to the radiator plates.

A negative reading on the device does not matter.

On the contrary, if there is even a small reading in the positive direction, it is necessary to change the radiator fan again.