The control system of level of oil consists of the oil level sensor which will be screwed through an opening for oil discharge, and a control lamp on the dashboard. Oil level in the pallet begins to be controlled at a temperature of oil of +60 °C.

Fig. 5.19. Oil level sensor: 1 – oil pallet; 2 – sealing ring; 3 – oil level sensor; 4 – air vent with a diameter of 8 mm; 5 – drain opening with a diameter of 4 mm; 6 – float; 7 – magnet; 8 – contact of the sensor; 9 – bimetallic washer valve

Oil level in the pallet decides on the help of a float. At the low level of oil under the influence of a magnet in the float-operated camera the contact of 8 (fig. 5.19) becomes isolated, on the dashboard the control lamp lights up. At the oil lowering of the level connected with traffic conditions, the control lamp at first blinks, then burns constantly.

To avoid the unnecessary preventions connected with the modes of the movement, for example at sharp turn the delay relay is installed in the control unit. It carries out inclusion of a control lamp if the signal of the low level of oil is given during 60 pages.

In order to avoid incorrect indications at the cold engine when not heated-up oil long flows down in the oil pallet, the sensor of level of oil is supplied with the bimetallic valve which interferes with discharge of oil from the float-operated camera. The sensor of level of oil provides inclusion of a control lamp on the dashboard shortly before the level of oil becomes minimum.

The sensor of level of oil transfers indications to the block of active system of the ASSYST service. The microcomputer on the basis of information obtained from various sensors, such as level and temperature of oil, temperature of cooling liquid, speed, speed and loading of the engine, registers actual state of engine oil and makes the plan for care of the engine. One of indicators of "ageing" of oil — contents of iron particles in it which sharply increases after 5000 km at the movement on short distances. Mercedes-Benz developed the special touch sensor. It heats up at the increased or lowered oil level, defines time of necessary replacement of oil, and also change of structure of oil, for example additives in it of metal, fuel or cooling liquid, and warns about it the driver. Information on the high or low level of oil is highlighted on the display of the dashboard.

Automatic indication begins to work not earlier than through 60 from later launch of the engine and at a temperature of oil more than +60 °C.

If the level of oil exceeds norm, then on the dashboard the butterdish symbol with the inscription "OLSTAND UBER MAX" accompanied by a sound signal is highlighted. Surplus of oil at the same time needs to be removed.

If oil level in the pallet low, then on the dashboard is highlighted a butterdish symbol with the inscription "OLSTAND UNTER MIN" accompanied by a sound signal. In this case it is necessary to fill as soon as possible oil level to norm.

At too small amount of oil on a combination of devices the butterdish symbol with the inscription "OLSTAND MINIMUM" (level of oil is lower than admissible) accompanied by a sound signal is highlighted. In this case it is necessary to fill immediately oil level to norm.

NOTE At the cars which do not have the multipurpose index near a butterdish symbol indication "-2L" is highlighted.

PREVENTION Information on oil level in the course of filling does not change. About the received amount of oil in the engine the system should be requested manually.

Switch off ignition. Install the ignition key in situation "2". Through 10 with on a combination of devices the message "OLSTAND ANZEEIGEN will appear?" ("To show oil level?") "butterdish" and "hours" symbols will also light up.

At this time within one second press the button installations in a starting position of the counter of a daily run twice. After a while the message, for example, of "1,0 L OI einfullen" will be highlighted ("To fill in 1,0 l of oil"). The message will appear not at once: at a temperature of oil of +60 °C of waiting time will make 1 min.

SEQUENCE OF WORKS

1. Remove from below a board of a motor compartment.

2. Merge or pump out engine oil by means of vacuum installation.

Fig. 5.20. Removal of the sensor of level of oil: 1 – contact socket; 2 – sealing ring; 3 – oil level sensor; 4 – bolt

3. Disconnect the contact socket 1 (fig. 5.20) from the oil level sensor.

4. Turn off a bolt 4.

5. Incline the sensor 3 levels of oil and take out it from the oil pallet.

6. Install the sensor 3 levels of oil with a new sealing ring 2 and wrap a bolt the 4th moment of 10 N · m.

7. Connect the contact socket 1 to the sensor.

8. Establish from below a board of a motor compartment.

9. Fill in engine oil in the engine.

10. Warm up the engine during a trial trip and check tightness of the sensor.

Addition for the 6-cylinder V-shaped engine:

1. Remove the lower part of the pallet of a case.

2. Unscrew from below screws of fastening (Torx) of the sensor of level of oil near a tube for oil pumping.

3. Bolts of fastening of the sensor of level of oil wrap the moment of 10 N · m.

SEQUENCE OF WORKS

1. Disconnect the oil level sensor socket.

2. An ohmmeter check contact between the sensor and "weight".

3. In the absence of contact remove and replace the sensor.

4. If the contact on the sensor is, check a chain from the sensor to a combination of devices.

5. If the chain is serviceable, then defect in a combination of devices can be a cause of defect.

6. Perhaps, the lamp fused. Replace it.

6. Disconnect a wire from the sensor.

7. Check contact between the socket of the sensor and "weight".

8. Under the above described conditions of contact on the sensor should not be. The break of a chain is possible.

9. If the lamp does not join, in the presence of contact on the sensor, the lamp means fused.

10. If there is no contact on the sensor, remove, check and if necessary replace the sensor.