golfvr6 highline

[mickthebrick 0]

why does fan run on for 10 mins before cutting out when engine switched off?

[VR6Pete 1,455]

Hi there Welcome to the Club

The only time I would expect the fan to run after the engine is switched off is when the engine has got very hot, you will probably find the aux pump is also running.

Does this happen only when the car is hot, or even if you just start the car and immediately turn it off again?

What temperature is your coolant running at?

The controller stays on for 10 minutes after you switch the car off (regardless of temperature) and will maintain power to the aux water pump. Stage 1 and 2 fans will come on if needed.

After you turn the ignition off after a long hot run, you should hear the faint whirr (or loud whirr/grinding if it's shagged) of the aux water pump and fan stage 1 or 2 will be on.

If you just turn the ignition on (even if the car is cold), you should hear the aux water pump whirring.

The idea behind the after-run pump is too circulate the water round the heater matrix and rear of the block to prevent localised over heating. Thus, the aux water pump runs regardless, come rain, shine, snow, ice and even if the engine hasn't even run (ignition on, then off).

Stage 1 has direct battery power and will run if it's triggered.

Stage 2 has power maintained to it only during the 10 min after run cycle and will also run only if tiggered.

Stage 3 is ignition only.

Fans/pump after-run fault-checking

You can use the following procedure to find out if your yellow temp sender is the cause of no after-run or not. This does not necessarily prove that the yellow temp sender is working, but it will prove if the circuitry that it controls is working or not.

Turn ignition key on, then off again

Disconnect the 4-pin connector from the yellow temperature sender switch

Bridge contacts B, D (brown/red and brown wire)

The radiator fan and auxiliary coolant pump must come on

If NO, check the fan control unit and/or the aux water pump.

I've moved this thread to the Engine problems section so you get a better response to your issue

Are you coming to our rolling road day on the 16th June?

Cheers,

Pete