BMW 740i car oil burning
  • Automotive

A mileage of about 112 thousand km, the F02 740i, the BMW 740i car equipped with N63 engine and 8 speed automatic transmission. The user reflects: the car burns the oil. Inspection and analysis: after the communication between the maintenance personnel and the users, it was found that there was a lot of oil alarm during the 2 oil maintenance. Every time the oil is added, the alarm will disappear. In order to determine the nature of the fault, the maintenance personnel decided to test the oil consumption of the vehicle first. After driving for 1000 km, the customer checked back and found that the oil consumption was 0.3 L. According to the manufacturer's regulations, the oil consumption is normal within 0.7 L. However, this test result contradict the situation reflected by users. The maintenance personnel inspected the engine parts carefully and found no signs of oil leakage. It is doubted that the measuring accuracy of the electronic gauge has a problem. After adding a certain amount of oil, the oil quantity display data were observed, and the data were found to be consistent with the oil volume change. Then check the crankcase ventilation system. Remove the ventilation pipe of the crankcase ventilation and find that there is only a small amount of oil in it. This problem can be ruled out. Measuring cylinder pressure, each cylinder is more than 1.2 MPa, no problem. Using the endoscope to check the cylinder wall, no signs of cylinder drawing were found. Looking back at the maintenance records of the car again, it was found that there were 3 engine oil alarms in the 7000 km, and the total oil volume increased to 5L. This indicates that during the observation of oil consumption, it is likely that the driving mode is different from the usual way, thus causing the false image of the oil consumption in the normal range. For this reason, the maintenance personnel decided to observe the engine oil burning phenomenon by using the intense driving mode. Then find a section of the open section, suddenly will accelerate the pedal to the end, when the vehicle in the rapid acceleration, from the exhaust pipe out of the blue smoke, so that the car does have oil burning phenomenon.