Oil Pump: Service and Repair
WM 172019 Removing and installing oil pump
Tools
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. The oil pressure control valve must be removed before the oil guide housing can be removed on the V6. The oil pressure control valve is blocking the installation position of the oil guide housing on the V6. -> 172619 Removing and installing oil pressure control valve Service and Repair
2. Remove oil pan and oil guide housing.
-> 175019 Removing and installing oil guide housing 175019 Removing and installing oil guide housing
Information
Component overview
Exploded drawing of oil pump balance shaft module
Oil pump with balance shaft
Tightening specifications for oil pump and balance shaft alignment
Oil pump chain guide
Oil pipes, fitted on oil pump and oil guide housing
Oil pipes, fitted on oil pump and oil guide housing (view without oil pan)
Information
Removing oil pump
Information
- The illustrations show the partly disassembled engine on the assembly support with oil pump facing upwards.
- The oil guide housing is removed.
- Adjustment operations on the balance shaft only work when the timing-case cover is fitted and the vibration balancer is connected.
Condition of component after removing the oil guide housing =>
View of oil pump with oil guide housing removed
1. Remove oil pump drive.
1.1. Turn the crankshaft vibration balancer as required until you can fit an open-ended wrench (a/f 36) on the balance weight on the balance shaft. Remove screw (M8 x 35) on the drive gear wheel for the oil pump. => Drive gear wheel for oil pump
Drive gear wheel for oil pump
1.2. Relieve the tensioning rail using a screwdriver (push it away) and remove the drive gear wheel for the oil pump. => Removing drive gear wheel for oil pump
Removing drive gear wheel for oil pump
1.3. Loosen counter-weight on the balance shaft. Counter at the intervention point with an open-ended wrench (a/f 36) and remove screw (M0 x 45) and tension cone. => Screw on counter-weight => Screw and tension cone for counter-weight
Screw on counter-weight
Screw and tension cone for counter-weight
Information
Make sure that small parts and the feather key do not fall off.
1.4. Loosen the counter-weight using pliers. When doing so, ensure that the feather key does not fall into the crankcase (place a cloth over the timing-case cover). => Loosening counter-weight on balance shaft
Loosening counter-weight on balance shaft
1.5. Remove the feather key from the counter-weight or balance shaft (depending on where the feather key is stuck) using pointed-nose pliers or a magnet. => Feather key for counter-weight => Securing feather key to prevent if from falling off
Feather key for counter-weight
Securing feather key to prevent if from falling off
2. Loosen drive sprocket for balance shaft. => Drive sprocket for balance shaft
Drive sprocket for balance shaft
3. Move the drive chain aside and remove the drive sprocket.
Drive chain
4. Loosen guide rail fastening point on the oil pump. To do this, remove two M6 screws. The bottom M6 screw, which is hidden by the timing-case cover, remains fitted.
Oil pump chain guide
5. Remove fastening screws from the oil pump (different sizes).
Oil pump with balance shaft
6. Lift up the oil pump and guide it out under the tensioning rail. Remove oil pump.
Installing oil pump
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 assemblies (e.g. chassis, electrics, transmission or body) or for peripheral engine equipment can be found in the corresponding documents.
1. The oil pump is installed in reverse order.
2. Before adjusting the balance shaft, check the following:
- The chain drive for the oil pump must be completely fitted. => View of oil pump with oil guide housing removed
- The balance weight is only screwed to the balance shaft when the feather key is inserted correctly and the balance shaft with counter-weight can be turned. -4-
- The timing-case cover must be fitted.
- The vibration balancer is connected.
- Have a staking pin locating pins 9595/1 and 6-mm drill bit or 6-mm screw ready.
View of oil pump with oil guide housing removed
2.1. Turn the crankshaft at the vibration balancer in direction of rotation to TDC position and lock at this position using a staking pin locating pins 9595/1.
2.1.1. Insert staking pin locating pins 9595/1 into the staking bore on the vibration balancer -2-.
Staking bore in vibration balancer
2.1.2. Turn the crankshaft at the vibration balancer -3- so that the staking pin in the vibration balancer slips into the lower staking point on the timing-case cover -1-. At the same time, exert gentle pressure on the staking pin while turning. Correct position of crankshaft. => Crankshaft at TDC position - balance shaft before adjustment
Staking position in timing-case cover
Crankshaft at TDC position - balance shaft before adjustment
2.2. Move the balance shaft at the counter-weight by pressing lightly with your fingers and turn it so that a 6-mm drill bit (or similar object) fits through the hole in the counter-weight into the adjustment bore in the chain guide. => Staking position of balance shaft -A-
Staking position of balance shaft
Tightening specifications for oil pump and balance shaft alignment
2.3. Counter the counter-weight with an open-ended wrench (a/f 36) in staked position and tighten the screw.
Securing counter-weight
Subsequent work
1. Install oil pan and oil guide housing.
-> 175019 Removing and installing oil guide housing 175019 Removing and installing oil guide housing