[bobthecabbage]

I've never had the fan run on my V40 (although I suspect my thermostat may be open at lower temps than it should be).

I don't think the diesel S40/V40s should need the fan to run on so I would expect that potentially a sensor issue or a coolant/pump issue.

I would check the temp using an OBDII scanner if possible to see if it is realistic and also check the hoses to the radiator to see if they are getting really hot.
My radiator fan only seems to kick in when the aircon is on and the car is stationary.

There is apparently some issue with the MAF sensor that can cause the fan to run at full tilt.

First off I would check the radiator is actually hot and also the temperature read out by OBDII if possible.

I would think it would be very unusual for the cooling fan to run for 3 minutes if every thing is working as it should.