Oil pressure check
1. Start the engine and warm it up to operating temperature (warming up determine the coolant temperature gauge). Take a ride on the car for a full guarantee. (In car workshops, the oil temperature is checked by inserting a temperature sensor into the guide tube of the oil level indicator. Regulated temperature – 90°C).
2. Remove the top of the air filter.
3. Turn out a stopper and remove it together with a sealing ring.
Note. The plug on a 4-cylinder engine is located in front on the right side of the cylinder block.
4. Screw in a manometer for measuring oil pressure instead of a plug, installing an o-ring.
5. Check the oil level, top up if necessary.
6. Start the engine and let it run at the idle speed. The oil pressure must be at least 0.3 bar, otherwise check the oil circuit.
7. Stop the engine.
8. Turn out the manometer.
9. Screw in the plug with the O-ring and tighten it to 40 Nm.
Addition for 6-cylinder in-line engine:
1. The pressure plug is located on the right side of the oil filter housing. The pressure values are given in table. 5.2.
Table 5.2. Oil pressure in the oil system of a 6-cylinder in-line engine
Screw in the plug, installing a new sealing ring, and tighten it with a torque of 15 Nm.
Supplement for 6-cylinder V-engine:
1. Remove the viscous fan.
2. Remove the fan shroud.
3. The pressure plug is located under the oil filter housing. The pressure values are given in table. 5.3.
Table 5.3. Oil pressure in the oil system of a 6-cylinder in-line engine
Screw in the plug, installing a new sealing ring, and tighten it with a torque of 20 Nm.
Oil pressure warning lamp
The oil pressure warning lamp lights up first of all when there is a lack of oil. In this case, engine components and parts receive little lubrication. This usually happens if the car is going through a corner at high speed with a low oil level. The oil pump sucks in air instead of oil. The oil pressure drops sharply, which can cause serious damage to the bearings.
Since the pressure is always correct at the required oil level, the oil pressure indicator has been abandoned in the E-Class models. Turning on the oil level warning light is a signal that you should always pay attention to.
The emergency oil pressure warning lamp lit up
1. If the oil pressure warning lamp flashes at idle after fast driving on a highway or mountain road, this is a signal that the oil pressure has dropped due to too high a temperature and, as a result, too low an oil viscosity. It is not dangerous if the lamp goes out when you press the accelerator pedal.
If the oil pressure warning light stays on
2. Stop immediately and turn off the engine.
3. Check the oil level, top up if necessary.
4. Check up, whether the control lamp burns again. In any case, you need to find out the reason. Have the vehicle towed to a service station. You can avoid serious engine damage.