Disassembly, inspection of technical condition and assembly of the oil pump (VW Passat B4)

To disassemble, unscrew the two bolts securing the oil pump cover to the housing. Separate the cover from the housing. Remove the drive shaft and the drive gear of the oil pump. Wash the pump housing with gasoline. If the oil pump parts are heavily contaminated, remove the oil receiver. Remove the mesh filter of the oil receiver and clean it.

Check the gap between the gear teeth, which should be 0.05 mm (maximum permissible 0.20 mm), and the gap between the outer diameter of the gears and the bore of the oil pump housing, which should be 0.15 mm (Fig. 3-24). Assemble the oil pump in the reverse order of disassembly.

Removal and installation of oil-water heat exchanger

The oil-water heat exchanger is installed only on turbocharged diesel engines.

Removing and installing the heat exchanger does not present any particular difficulties. Remove the oil filter, then the heat exchanger. When installing, apply a layer of sealant to the mating surface of the heat exchanger with the oil filter bracket around the sealing ring.

Checking the oil pressure in the lubrication system

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Disconnect the wires from the oil pressure sensor, unscrew the sensor and screw in the nipple of the test pressure gauge hose instead. Start and warm up the engine to an oil temperature of 80°C in the system. Measure the oil pressure at idle and at a crankshaft speed of 2000 rpm, which should be 0.15-0.45 kgf/cm², respectively, and at least 2.0 kgf/cm² for oil of viscosity grade 10W40. Disconnect the test pressure gauge, screw in the oil pressure sensor and connect the wire to it.