We bought a car today. The engine has a constant hum it does not go away. The previous owner says he always treated the car with care, but he had the humming right from the start and it wouldn't have caused him any problems. Now I wonder what that could be. Before I go to the workshop, I would like to ask you for advice.
In addition, a lack of acceleration can be felt, so, according to my father, a loss of power and high consumption.
Could it be that the BMW is getting bad air?