Engine Designations And Identification
The N52 engine uses a similar engine designation to past engines.
The new engine designation is broken down as follows
Scheme 51
The "OL" designation refers to the upper output stage, the "UL" designation refers to the lower output engine which is not available in the US market. Both, the N52B30 and B25 engine will only be available as the "OL" variant in the US.
The engine identification code is located on the side of the engine block, below the intake manifold directly between the knock sensors. The designation "AF" in the engine code refers to the upper output stage or "OL" variant.
Scheme 52
Oil Pump Operation
The crankshaft drives the pump with a chain. The applied oil pressure acts on the control spool with oblique stop face (pendulum support) against the force of a compression spring. The pendulum support varies the position of the slide valve. The changes in volume are small and the delivered volume is low when the pump shaft is positioned towards the center of the slide valve. The changes in volume and the delivered quantity are greater than the pump shaft is located off center. If the oil required by the engine increases, for example, VANOS control intervention, the pressure in the lubricating system drops and is therefore also reduced at the control spool. In response, the pump increases the delivery volume and re-establishes the pressure conditions. When the oil required by the engine decreases, the pump correspondingly reduces the delivery quantity towards the zero-delivery direction.
Scheme 53
Dynamic oil level measurement during vehicle operation
Always perform the dynamic oil level measurement (app.. 5 minutes driving time) after an oil change. The oil level could be misinterpreted as the oil level last stored is initially displayed after an oil change.
No oil level is initially stored after replacing or reprogramming the engine control unit. "Oil level below min" is therefore displayed. The correct oil level is indicated after running the engine for app.. 5 minutes.
- Start engine.
- Select on-board computer function - "Check oil level".
- The oil level is measured. A clock symbol may appear while the level measurement is running. The clock symbol appears for up to 50 seconds after starting the engine when there is no measured value or the long-term value last stored is not within the tolerance range of the currently measured oil level.
Scheme 54
Synamic oil level measurement begins when following values are reached
- Engine temperature > 60°C
- Engine speed > 1000 RPM
- Transverse and longitudinal acceleration < 4-5 m/s2
The transverse acceleration signal is supplied by the DSC. The longitudinal acceleration is calculated from the speed and time factors.
- Increase < 5% after covering a distance of app.. 200 m. The increase value is detected by the ambient pressure sensor in the DME.
On reaching this value, the oil level indicator is updated approximately 5 minutes after starting vehicle operation. The oil level is then continuously measured. The indicator is updated at 20 minute intervals. The "Check oil level" menu in connection with the dynamic oil level measurement is exited while driving (vehicle speed > 0) app.. 15 seconds after the oil level is displayed.
