Checking oil pressure sensors 0.3 bar
Installed 2 oil pressure sensors, triggered at different oil pressures. The 0.3 bar oil pressure switch has brown insulation; 1.8 bar oil pressure sensor has white insulation. Instead of a 1.8 bar oil pressure sensor, the diesel engine has a 0.9 bar sensor with gray insulation.
4 cylinder engine
The 0.3 bar oil pressure sensor is located on the front side of the cylinder head on the left in the engine compartment. Oil pressure sensors 1.8/0.9 bar are screwed on top of the oil filter bracket.
5 cylinder engine
Both oil pressure sensors are located on the left side of the cylinder block in front of the oil level indicator pilot hole.
1. Check oil level.
2. Check the wiring of both oil pressure sensors according to the wiring diagram.
3. Remove oil pressure sensor 0.3 bar (brown insulation).
4. Screw in a suitable pressure gauge instead of the oil pressure sender.
5. If a VW gauge is to be used, screw the oil pressure switch to the test gauge.
Attention! The test described can only be carried out if it is possible to screw the sensor into the pressure gauge. Otherwise, only 1.8/0.9 bar sensors can be tested.
6. Connect tester to ground (-).
7. Connect, using an additional wire, a voltage measuring device (multimeter or diode indicator) to oil pressure sensor 0.3 (A) and the positive battery terminal.
8. The control lamp or LED should light up.
9. Start the engine and gradually increase the speed.
10. As soon as the pressure gauge shows 0.15–0.45 bar, but no more, the control lamp goes out. If not, replace oil pressure sensor 0.3 bar.
Attention! If necessary, check the moment of operation of the oil pressure sensor when the engine is rotated by the starter.
Oil pressure sensors 1.8/0.9 bar
11. Disconnect wiring from sensor 1.8/0.9 bar (white/grey insulation).
12. Using an additional wire, connect a voltage measuring device (multimeter or diode indicator) to the oil pressure switch 1.8/0.9 bar and to the positive pole of the battery.
13. The control lamp should not light up.
Oil pressure sensor 1.8 bar
14. Raise the speed until the gauge shows 1.6 to 1.8 bar. Now the control lamp should light up, otherwise replace the oil pressure sensor.
Oil pressure sensor 0.9 bar
15. Raise the speed until the gauge shows 0.75 to 1.05 bar. Now the control lamp should light up, otherwise replace the oil pressure sensor.
Oil pressure check
1. Raise the speed to 2000 rpm. At an oil temperature of 80°C, the oil pressure at these speeds must be at least 2.0 bar.
2. Less oil pressure indicates worn crankshaft main bearings.
3. Raise the revs even higher. The oil pressure must not exceed the maximum allowable value. Otherwise, replace the oil pump cover with overpressure valve.
4. Install the oil pressure switch with a new O-ring and tighten to 25 Nm.
Maximum allowable oil pressure
Engine | Maximum oil pressure, bar |
4 cylinder engine | 7,0 |
5 cylinder engine | 5,3 – 6,3 |
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