One problem related to engine cooling system has been reported for the 2008 Mini Cooper S. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2008 Mini Cooper S based on all problems reported for the 2008 Cooper S.
Leaving from work around 5:00 pm (car had been in the parking lot since 7:20 am), I drove for a mile or less when at a red light the car by my side told me about smoke coming from the under the hood. I drove to the closet parking lot, opened the hood (there was a lot of smoke) and I could see 2 wires red hot. I went to try to get a fire extinguisher and luckily and ambulance on duty (could not help me because he had a patient) gave me a small bottle of water. When I returned to the car with the water there were flames about 10" tall on a small area, already touching the pipes the come out of the turbo (pipes that bring air into turbo and out to the intercooler) and with the 500ml bottle of water I was able to put it off. Daler (Mini of sterling) repaired the vehicle for free (car is under warranty). Dealer found that the auxiliary water pump shorted, and this must have cause the wires to overheat. Dealer replaced auxiliary water pump and wires and parts that burned. I spoke with the dealer and then with Mini USA, both refused to change engineering to prevent a future fire in case auxiliary water pump has a short-circuit again. Updated 1/27/2012.