Is My CPU Cooler Fan Broken?

Hello,

The radiator fan on my AFN engine doesn't turn on, even when the oil temperature reaches 100°C. However, the water temperature remains within the 'normal' range; the gauge needle has never left the 'middle' position. When the air conditioning is turned on, the fan immediately starts. At an outside temperature of 30-35°C and increased air conditioning demand, it also switches to level II.
Do I need to worry?

Regards,

Tobias.

Hello,

I can only provide information about two-stage fans, and I'm not sure if that applies to your AFN model.

A two-stage cooler fan is controlled by the following factors:
Water temperature > 105 (?) ° = Stage 1.
Water temperature > 115 (?) ° = second stage.
Climate on = first level.
Refrigerant for climate control, hot = second stage.

If multiple events occur, the highest level is always activated.

The oil temperature is not checked. (Often, there is no separate oil cooler, but rather an oil-water heat exchanger.)

Regards,
Private.

Hello,

Thank you for your contribution. The AFN should also have a two-stage fan. The 'Jetzt helfe ich miur selbst' manual also includes the temperature values at which the fan should start.

Regards,

Tobias.

Hello!!

It is definitely true that the oil temperature has nothing to do with the fan starting up.
It only depends on the coolant or air conditioning system pressure ).

Greetings.

Sure, here is the translation of the text from German to English:

'Nic'

Hello Nic,

Since the vehicle has a water-oil heat exchanger, the oil and water temperatures should be approximately the same, right?

Regards,

Tobias.

It should theoretically be like that.

However, the turbocharger heats the oil so much that it needs to be cooled by water.

Oil temperatures are (as far as I know) normal up to ~120°C, and the coolant should not be like that .

Is everything clear?


Therefore, also the water/oil cooler ).

To wrote:

Since the vehicle has a water-oil heat exchanger, the oil and water temperatures should be approximately the same, right?

A heat exchanger, or more accurately a heat exchanger, always has a temperature difference between the two media. True counter-current heat exchangers theoretically do not, but cross-flow heat exchangers are much cheaper to manufacture.
Furthermore, the oil temperature should be measured directly behind the turbocharger. However, heat is also dissipated by the oil-cooled pistons (and by all other components, just like in "normal" engines).

Hello,

Okay, let me rephrase the question: Does the fan run at speed level I during 'normal' operation? (of course, with the air conditioning turned off).

Regards,

Tobias.

Hello Tobias,

If there is a fuse box directly attached to the battery, check the fuses inside to ensure they are making proper contact and have not blown.

Best regards, Rainer.

Hello Rainer,

There's no fuse box. I guess they didn't include it until the Golf IV; I still have a Golf III.

Regards,

Tobias.

It should be located next to the coolant reservoir, on the right-hand side when facing forward. It's a block of approximately 6x12cm with two fuses in the front section and should be clearly visible.

Well, that's how it was with mine...

Regards,
Private.

To wrote:

Hello Rainer, There's no fuse box. I guess they didn't include it until the Golf IV; I still have a Golf III. Regards, Tobias

Okay, be glad, because mine started peeling off after only 3 years, so that the first stage of the fan stopped working.

Best regards, Rainer.

@private

Based on my gut feeling, I would say that in this area, only the strip heater is used for the fan after-run.

@Rainer
'Unfortunately, that doesn't apply to me, but thank you for your contribution!'

Regards,

Tobias.

Why should this fuse be specifically for the fan after-run ?

'In my 1997 AHU, both fuses (stage 1 and 2) and the entire relay that controls the fan are all housed together in a single unit. The fuse for stage two is a strip fuse (I believe it's 50A), while the fuse for stage one is a standard automotive flat blade fuse (with... let me check my crystal ball... approximately 30A).'

Take a closer look; I'd be surprised if it's different for you.

Regards,
Private.

Hello,

Okay, I need to take another look, but the fan is running when I turn on the air conditioning, so it probably isn't a fuse issue. Maybe everything is actually okay?

Regards,

Tobias.