Engine Lubrication: Description and Operation

Determination Of Oil Level

Oil level measurement is performed while driving, over 30 miles (50 km), as well as with warm engine (oil temperature > 149° F./65° C.) and horizontally parked vehicle (engine off > 120 sec.) and ignition on.

Determination for topping up oil







The oil level is reset after the hood is opened. The oil level can be measured immediately if the hood is closed. Required: Oil temperature > 149° F. (65° C.) and engine is off for longer than 120 sec. If the preconditions are not met, the following message appears in the multi-function display: "Oil level available only after short time/distance".

If the vehicle is driven off immediately after opening the hood without the conditions being met, it is necessary either to drive for a minimum of 30 miles (50 km) or the vehicle must stopped with the engine off for 2 min with an oil temperature of > 149° F. (65° C.) in order to call up the oil level in the multi-function display.

The quantity difference between the minimum and maximum markings is approx. 1 liter. One segment on the display corresponds to a top-up quantity of 0.25 liters. If the oil-level indicator fails, the message "Failure Oil level measurement" appears on the multi-function display.

Further operation-specific information is provided in the Owner's Data.

Oil level sensor

The oil level sensor is a PULS (Packaged Ultrasonic Level Sensor) sensor. Among other things, the advantage of this sensor is that it can detect both a minimum and maximum oil level as well as overfilling. It works according to the principle of ultrasonic measurement.

The ultrasonic sensor is a continually operating sensor system for detection of the engine oil level. The determined fill-level data is supplied via a pulse-width modulated signal.

The displayed oil level is calculated from a long-term mean value. The mean value is calculated over 30 miles (50 km) and 3,600 measured values. When the mean value has been calculated, the last mean value is stored and mean value calculation starts all over again.







Only measured values that were obtained within certain temperature, engine speed, vehicle speed and lateral acceleration thresholds (enabling signal from DME) are used for calculating mean values.

The last mean value is always displayed in the Oil menu; oil level display is always possible except for after opening the hood.