Zetec radiator fan

[drip]

My 2007 Mondeo Zetec was in an accident a couple of months ago and ever since it came back from the repairers the radiator fan seems louder and seems to stay on a lot longer after the engine is off. Even if you've only gone for a casual cruise or a hard run, warm or cool day, when the car is turned off the radiator fan keeps running for a good 3-5 minutes. Is this normal? How long do other Mondeos keep their fans running for? I mentioned it to the repairers and they reckon they checked it and it was normal but I had no end of trouble getting them to fix things properly. Any input appreciated. Thanks