One problem related to coolant leaking has been reported for the 2012 BMW 528. The most recently reported issues are listed below.
Turbo charger system is affected due to the engine oil filter housing failing which caused oil to transfer through out the turbo system into the coolant reservoir resulting in black sludge that caused my car to stall and not run and have to be towed. Every since this recall issue my car gives the drive-train malfunction warning which when diagnosed indicates low turbo boost pressure which I'm certain has to do with the black sludge that ran through the turbo system and coolant system because of the engine oil filter housing failing. A software update was recommended that BMW is not willing to pay for or I need to pay $3660 to replace the turbo charger which I truly believe is the result of the oil filter housing fail and oil leaking into the turbo system and the coolant system.