Radiator fan remains on for 4 or 5 minutes after ignition turned off

PeterC3 wrote: ↑Tue Jul 16, 2019 2:39 pm Hi all, hoping someone could advise. I inherited my wifes 65 plate C3 Picasso and all is good with it. However as the weather has got a little warmer I have had the aircon on. This is potentially my problem.

I put the aircon on and 30 seconds later the radiator fan comes on, enough to just about hear it in the car. Fairly loud. Then when stopped and ignition turned off, the radiator fan remains on and at that volume for a further 4 or 5 minutes. Is this normal? Is it a symptom of something else?

Thanks.

Arfur Dent wrote: ↑Tue Jul 16, 2019 3:51 pm

PeterC3 wrote: ↑Tue Jul 16, 2019 2:39 pm Hi all, hoping someone could advise. I inherited my wifes 65 plate C3 Picasso and all is good with it. However as the weather has got a little warmer I have had the aircon on. This is potentially my problem.

I put the aircon on and 30 seconds later the radiator fan comes on, enough to just about hear it in the car. Fairly loud. Then when stopped and ignition turned off, the radiator fan remains on and at that volume for a further 4 or 5 minutes. Is this normal? Is it a symptom of something else?

Thanks.

Hello PeterC3

does your C3 Picasso have a temperature gauge on the dash and does it stay in the normal range?

Ozvtr wrote: ↑Wed Jul 17, 2019 4:11 am When in use, the air-conditioning condenser (in front of the radiator) will get hot. The radiator thermo fan doubles up as a cooling fan for the aircon condenser. When you are driving down the road, typically, air moving through the grill is sufficient to cool things down but not when stationary. So when the aircon is on and the car is at low speed or stopped, the fan will run. With the aircon on you are drawing hot air across the radiator (another thing you are trying to cool down) from the hot condenser. Yep, not the greatest of ideas but the best compromise of space and resources. That means to cool down the radiator and the condenser, on a hot day when the car has stopped, the fan is going to have its’ work cut out for it and will probably run flat out.
Most thermo fans turn off with the ignition (or run on for a few seconds) but I am unfamiliar with operation of the diesels’ fan. It may run on to cool down the engine bay because of the turbo but that’s only a guess.
As long as the over temp light on your dash remains off AND your expansion tank doesn’t boil over AND the radiator fan turns off (eventually)…I wouldn’t worry.