Engine Oil Pressure: Testing and Inspection

Oil pressure and oil pressure switch, checking





Special tools, testers and auxiliary items required
^ Oil pressure tester V.A.G 1342
^ Voltage tester V.A.G 1527B
^ Adapter set V.A.G 1594A

Function of the dynamic oil pressure warning device

When not under pressure, the oil pressure switch is open and will close when the operating pressure is attained.

The oil pressure warning will be activated approx. 10 seconds after switching ignition on.

Switch-on delay of oil pressure warning: Approx. 3 seconds

Switch-off delay of oil pressure warning: Approx. 5 seconds

Checking warning light
After switching on the ignition with the engine not started, the oil pressure warning lamp in the instrument cluster must light up for approx. 3 seconds and then go out. The test will be terminated if the engine is running.

Criteria for warning
Switching on the optical oil pressure warning (the oil pressure warning lamp flashes) and the buzzer sounding three times for the acoustical warning will occur under one of the following conditions.
^ "Ignition on", engine not running, oil pressure switch closed.
^ Engine revolutions above 1500 rpm, oil pressure switch open

Note:
^ At engine revolutions greater than 5000 rpm the oil pressure warning will not be triggered, even when the oil pressure switch is closed. At engine revolutions under 5000 rpm, the oil pressure warning will go out.
^ If the oil pressure switch is open for only 0.5 to 3.0 seconds when engine revolutions are above 1500 rpm the occurrence will be stored in the processor of the instrument cluster. If this condition occurs three times when the engine is running, the oil pressure warning will be activated immediately and will not be cancelled even below 1500 rpm. The oil pressure warning will be cancelled when the oil pressure switch is closed for longer than 5 seconds at an engine speed above 1500 rpm or when the ignition is switched off.

Requirements
^ If engine oil level is OK, check or
^ Oil pressure warning lamp -K3- must light up for approx. 3 seconds when ignition is switched on.
^ Coolant temperature at least 80° C (radiator coolant fan must have run once)

Work sequence





- Remove oil pressure switch Oil pressure switch -F1- and screw into tester.
- Screw tester into oil filter bracket in place of oil pressure switch.
- Connect brown wire of tester to Ground (-).
- Connect voltage tester V.A.G 1527B using auxiliary cables V.A.G 1594A to battery positive (+) and oil pressure switch.
- LED must not light up
- If LED lights up, replace 1.4 bar Oil pressure switch -F1-.

If LED does not light up:
- Start engine and run at idling speed:
- At 1.2 to 1.6 bar LED must light up; otherwise replace oil pressure switch.
- Increase engine speed.
- At 2000 rpm and an oil temperature of 80° C oil pressure should be between 2.7 to 4.5 bar

At higher engine speeds, the oil pressure must not exceed 7.0 bar.

If the specifications are not obtained:
- Check strainer in suction pipe for soiling.

Note:
^ Mechanical damages, e.g. bearing damage, could also be the cause for low oil pressure.

If no faults are found:
- Replace oil pump.

If the specification is exceeded:
- Check oil passages.
- If necessary, replace oil filter bracket with pressure relief valve.