Coolant problem?

[Ignitor]

Hi, i've owned my '05 2.0i SE for 3 days now and its been an absolute joy. After a lazy Sunday afternoon drive through the country lanes i parked up and switched off the engine, stepped out, locked up, and thought 'wow, my ankles are damn hot'. I felt below the door sills and there was a serious blast of warm air and a whirring sound from the engine compartment. I put my hand in front of the radiator grilles and felt that they were sucking air in.
Now, the car's temp gauge was normal, it was running great, it hadn't been thrashed and once i'd re-started the engine and then switched off again the whirring and blast of warm air from underneath just stopped. I'm a total noobie at Z4 ownership, so please forgive me if this totally normal.
Could someone reassure me that's all cool (no pun intended ) and i shouldn't worry, or should i get the car to the dealership asap? My car is due an oil service in 650 miles, if thats of any relevance, and there are no warning lights or anything else to hint that somethings up, so any info/advice would be greatly appreciated by this complete novice .
Ignitor.

[plowy]

Quite normal, operation of the electric fan, it's still whirring away after you've stopped sucking in cool air and throwing the warm air out, they work on a thermostat, nothing to worry about..

[Ignitor]

Geezer! Cheers mate. I warned that i'd be asking daft questions when i joined up