Checking oil pressure and oil pressure sensor (VW Polo 4)

A pressure gauge with a threaded hole for screwing in the hydraulic switch is required for checking. The location of the hydraulic switch depends on the engine version. Petrol engine with a working volume of 1.2/1.4 l (except FSI), on the left end of the cylinder head.

1.4 l FSI petrol engine: Left front on cylinder head, see position "14" on figure N15-0650.

Diesel engine: on the oil filter bracket.

Examination

Check and, if necessary, adjust the engine oil level.

Warm up the engine to operating temperature and let it idle until the radiator fan turns on and off once.



Unscrew the hydraulic switch "2" and screw it into the measuring device "A".

Screw the oil pressure gauge into the hydraulic switch hole.

Connect the brown wire "1" of the measuring device to ground (-).

Connect the semiconductor diode test lamp to the positive pole (+) of the battery and to the hydraulic switch.

The LED should not light up.

If the LED lights up, replace the hydraulic switch.

If the LED does not light:

Start the engine.

Caution: When starting the engine, observe the measuring instrument and the LED indicator lamp, since the response pressure of the hydraulic switch may already be exceeded when starting the engine.

(The information is posted on this resource VWmanual)

Slowly increase the engine speed. When the response pressure range is reached, the LED should light up, otherwise replace the hydraulic switch.

Checking oil pressure

Increase the engine crankshaft speed to 20,001/min. The engine oil pressure must be at least 2.0 bar.

If the prescribed pressure value is not achieved:

Check the engine for mechanical damage, such as damage to the crankshaft bearings (at a service station).

If necessary, replace the oil filter bracket together with the pressure reducing valve or, respectively, the oil pump.

Caution: At higher engine speeds, the engine oil pressure must not exceed 7.0 bar (for a 1.4 l diesel engine: 5.8 bar). Otherwise, check the oil passages. If necessary, replace the oil filter bracket together with the pressure reducing valve.

Additional information: 1.4 l FSI petrol engine: Oil filter cover with 2.5 bar bypass valve.

1.4 l TDI engine: oil pump with 11.5 bar pressure reducing valve.

1.9 l SDI/TDI engine: oil pump with 12 bar pressure reducing valve.