Removal and Replacement
WM 172019 Removing and installing oil pump
Preliminary work
Information
If vehicles have fault entries relating to oil pressure, oil pump activation, oil pressure monitoring, etc. in the DME control unit (and a warning light comes "on" on the instrument cluster), proceed as follows:
- Check the oil level.
- Delete related faults.
- Do not replace components, such as the oil pump, oil pressure sensor or oil pressure control valve if you suspect that they are faulty.
If the vehicle has not been driven for a long time (months), the control mechanism in the oil pump can become stiff ("stick").
Very short trips and a lot of loading/manoeuvring can cause the oil to become very diluted => Oil pressure very low. For example, 20 cold starts in quick succession can reduce the viscosity of the engine oil by 30%.
- Change the engine oil. Test-drive the vehicle.
- If error messages/warnings are displayed again, proceed in accordance with the instructions under Guided Fault Finding in the PIWIS Tester.
1. Remove oil pan and oil guide housing.
-> 175019 Removing and installing oil guide housing 175019 Removing and installing oil guide housing
Information
Component overview
Oil pump, turbo engine
Oil pump, naturally aspirated engine
Suction tube for auxiliary sump
Information
The tightening specifications for the basic engine are stored centrally. -> 1001IN Tightening torques, tightening sequences, assembly overviews [1][2]Specifications. Tightening torques and assembly instructions for other affected assemblies (e.g. chassis, electrics, transmission or body) or for peripheral engine equipment can be found in the corresponding documents.
Information
- The oil pump must not be disassembled and reassembled!
- When carrying out work on the oil circuit, it must be ensured that no dirt gets into the engine!
Information
- The oil pump can be replaced while installed.
Removing oil pump
1. Remove suction tube for auxiliary sump.
1.1. Loosen fastening screw -arrow- on suction tube.
Screw on suction tube
1.2. Loosen and remove suction tube, fastening screw and seal from the guide.
1.3. Make sure that the suction tube and the related seal -arrow- are removed from the oil pump guide.
Seal on suction tube
2. Remove the sprocket cover for the oil pump
2.1. Unscrew fastening screws -2- and -3- on the sprocket cover.
Fastening screws on sprocket cover
2.2. Loosen the three fastening screws -arrows- on the oil pump.
Fastening screws for oil pump
2.3. The oil pump can now be moved down slightly because the fastening screws have been loosened.
2.4. Loosen fastening screw -1- on the chain cover.
Fastening screw on chain cover
2.5. Pull sprocket cover down and off. The top hole is open. => Top threaded joint on sprocket cover
Top threaded joint on sprocket cover
3. Remove the oil pump drive sprocket.
3.1. Position vibration balancer with screw tightened hand-tight on the crankshaft stub. Attach change-over ratchet => Screw on sprocket.
Screw on sprocket
3.2. Loosen screw on sprocket. Use an extension if necessary because the screw is very tight -1-. Counter at the vibration balancer using the change-over ratchet. The loosened screw must not be re-used.
3.3. Counter the very tight screw with a screwdriver if necessary => Loosening fastening screw on sprocket.
Loosening fastening screw on sprocket
3.4. Press off small tensioning rail on the chain -arrow- using a screwdriver => Oil pump drive chain and remove the sprocket from the pump. Loosen the tensioning rail slowly. The chain remains fitted.
Oil pump drive chain
4. Remove the oil pump.
4.1. Loosen the three fastening screws -arrows- on the oil pump fully and remove the oil pump.
Fastening screws on oil pump
Installing oil pump
1. Fit the oil pump drive sprocket.
1.1. Fit the oil pump => Fit the oil pump and screw in the three fastening screws.
Fit the oil pump
1.2. Screw in the fastening screws on the oil pump so that it can still be moved slightly.
1.3. Press down the small tensioning rail for the chain -arrow- using a screwdriver => Oil pump drive chain.
Oil pump drive chain
1.4. Fit the sprocket and screw in a new fastening screw.
1.5. Tighten the fastening screw and counter at the same time with a screwdriver.
Tightening fastening screw on sprocket
1.6. Check that the tensioning rail and drive chain are positioned correctly.
2. Fit oil pump sprocket cover.
2.1. Slide in sprocket cover in an upward direction. The top hole is open. The screw -1- is still fitted, but loosened. => Top threaded joint on sprocket cover
Top threaded joint on sprocket cover
2.2. The oil pump can be moved down slightly because the fastening screws have been loosened.
2.3. Tighten the top screw -1- (tighten sufficiently by hand). Fit the two remaining screws -2 and 3 -.
Fastening screws on sprocket cover
3. Fit the oil pump.
3.1. Fit the oil pump again.
3.2. Tighten the three fastening screws -arrows- on the oil pump fully.
Fastening screws on oil pump
4. Fit suction tube for auxiliary sump.
4.1. Replace seal on oil return pipe connection.
4.2. Hook the suction tube into the guide.
Suction tube guide
4.3. Carefully press the suction tube connection piece into the hole provided for it on the oil pump with your hand.
4.4. Fit the fastening screw -arrow- on the suction tube.
Suction tube screw
Subsequent work
1. Install oil pan and oil guide housing.
-> 175019 Removing and installing oil guide housing 175019 Removing and installing oil guide housing