Oil Pan: Service and Repair
Removing and installing oil sump (4MATIC front axle housing)Preceding work:
- Hood raised to vertical position.
- Bottom engine compartment panel removed.
- Air cleaner removed.
- Fan shroud removed.
- Disconnect ground cable at battery
- Drain engine oil (step 2)
- Unbolt both front engine mounts (526) from below
- Remove torsion bar
- Remove dipstick guide tube, 10 Nm (steps 5 - 6)
- Remove drag link (428) together with steering damper (431)
- Unbolt exhaust system at flange of exhaust manifold (step 8)
- Unbolt front propeller shaft (70) (step 9)
- Unbolt front axle shafts (59) (steps 10 - 11)
- Unplug plug connection of oil level switch at oil sump or front axle housing (step 12)
- Remove bottom part of oil sump (4), 10 Nm (step 13)
- Remove support (554) for oil pump (542) (step 14)
- Insert guard plate at component compartment wall (step 15)
- Raise engine (steps 16 - 17)
- Position pistons of cylinders 3 and 4 to TDC (step 18)
- Remove left engine support (122) at crankcase, M8 20 Nm (step 19)
- Unbolt front axle housing (588) (step 20), M6 = 10 Nm, M8 = 22 Nm.
- Apply sealant 001 98945 20 10 to contact surfaces of front axle housing (step 22)
- Remove oil pump (542), 25 Nm (step 21)
Tightening torques in Nm
Oil sump to crankcase
M6 hexagon bolts 10
M8 hexagon bolts 25
M10 hexagon bolts 40
Oil pipes at oil sump 10
Dipstick guide tube to front axle housing 10
Special Tools:
Shop Made Tools:
Removal, installation
1 Disconnect ground cable at the battery.
2 Drain engine oil
Note: Unscrew oil drain plug (arrow) at the large oil sump (4)
3 Unbolt front engine mounts from below
4 Remove front torsion bar
Dipstick Guide Tube:
5 Unbolt bracket of dipstick guide tube (24) at the exhaust manifold.
6 Unscrew bolt (23) and withdraw dipstick guide tube (24) from front axle housing.
Installation Note: Tightening torque 10 Nm.
Drag Link & Steering Damper:
7. Unbolt steering damper (431) at body and remove drag link (428).
Exhaust Flange Bolts:
8. Unscrew bolts (arrows) for exhaust system on the flange of the exhaust manifold.
9. Unscrew propeller shaft (70) to front axle at front axle housing. To do this, counter-hold the connecting flange with 65 mm open-end wrench and unscrew six bolts.
Caution: Do not counter-hold at the clamping nut (70e). Ensure that the connecting flange is not pushed out of the splines.
Installation note: Replace self locking bolts. Pay attention to tightening torque.
10. Unbolt front axle shafts (59). Operate the footbrake in order to slacken the six bolts.
Installation note: Replace self locking bolts. Pay attention to tightening torque.
11. Push front axle shaft (59) together as far as possible and fix in this position with wire. Place axle shafts down on the wishbone.
Caution: Do not pull inner joint too far apart, otherwise rollers may fall out!
12 Unplug connector (arrow) of the oil level sensor on the left at oil sump and at front axle housing, respectively.
13 Unscrew bolts for bottom section of oil sump (4) and take off bottom section of sump (4).
Installation note: Tightening torque 10 Nm.
14 Unscrew bolts (2) and bolt (3). Take off support (1) at intake snorkel of oil pump.
15 Insert guard plate (arrow) between component compartment wall and engine.
16 Attach engine hoist to front suspension lug.
17 Raise engine slightly.
Caution! When raising the engine, ensure that the fan does not damage the radiator and also pay attention to the rear suspension lug, oil filter and coolant hoses.
18 Position pistons of cylinders 3 and 4 to TDC.
The pistons of cylinders 3 and 4 are at the TDC position when the marking "a" on the vibration damper is aimed with the TDC pointer.
19 Unbolt left-hand engine support at the crankcase and take off together with engine mount.
Installation note: Tightening torque 25 Nm.
20 Unbolt front axle housing from transmission and crankcase. Support front axle housing.
On vehicles fitted with automatic transmission, unbolt the oil pipe from and to the transmission along the front axle housing.
Note: The M8 bolts (arrows) on the left side of the engine can be reached from above. To turn the two bolts below the starter, position screwdriver bit between starter and crankcase.
21 Lower front axle housing as far as possible. Unscrew bolt for sprocket (1) and take oft sprocket (1). Unscrew bolts (arrows) and take out oil pump downward. Take off front axle housing to the rear. Pay attention to drive chain of oil pump.
Installation note Tightening torques: Bolts of sprocket 30 Nm / Bolts of oil pump 25 Nm
22 Clean contact surfaces on front axle housing. Apply sealant 001 989 45 20 10 to the contact surface on front axle housing (a = silicon bead ~ 1.5 mm). First mate front axle housing to the transmission, then bolt to crankcase.
Installation note
Pay attention to different lengths of bolts.
Tightening torque
M6 = 10 Nm
M8 = 21 Nm
Replace self-locking bolts and nuts.
Installation is performed in the reverse order.