i work for a bmw dealership here in new jersey,first off,bmws are tuff,their engines are top notch ,something ford should learn about,i would bring the car to a bmw dealer and have them check it out,have them run for any faults,just because a service engine soon light is not on it does not mean there are no faults,have them do a pressure check on cooling system, check for any oil leaks ,and check operation of crankcase vent valves, and compression check of all cylinders,if eveything is ok do a coolant flush and oil service with filterbmw did have a recall on ignition coils ,see if its involved ,explain situation with service manager i do belive he will agree,any service records with car ,my email is
[email protected]. keep me posted, i do know alot and have many friends at the dealership and with bmw