1001Z2 Disassembling V8 4.8-litre DFI engine
WM 1001Z1 Disassembling V8 4.8-litre DFI engine
Tools
Preliminary work
1. Remove engine. -> 100119 Removing and installing V8 4.8-litre DFI engine - section on "Removing" 100119 Removing and installing V8 4.8-litre DFI engine
2. Remove engine from transmission. -> 100127 Removing engine from transmission and mounting engine on transmission - section on "Removing" 100127 Removing engine from transmission and mounting engine on transmission
3. Secure engine on assembly support. -> 1001IN Securing V8 4.8-litre DFI engine on mounting bracket 1001IN Securing V8 4.8l DFI engine on the mounting bracket
4. Drain engine oil. For details, see -> 170117 Changing engine oil and oil filter on DFI engines - section on "Draining and filling" Service and Repair
Disassembling V8 4.8-litre DFI engine
CAUTION
Emerging residual fluid can soil the engine!
- Residual fluid (fuel, oil, Pentosin, coolant, etc.) will emerge even after a long time when disassembling and assembling the engine.
-> Place a drip tray under the engine at the assembly support.
-> Have a sufficient number of cleaning cloths ready.
-> Close off engine openings with plugs.
CAUTION
Interchanged or dirty bucket tappets.
- Damage to engine components.
-> The components have been run in in the fitting bores in the housing, therefore do not interchange them.
-> Absolute cleanliness is essential.
Information
For many components, it is only necessary to partially disassemble the engine. The extent of disassembly depends on the damage and scope of repairs to be carried out.
When replacing the cylinder head gasket, many components, such as the DFI high-pressure pump, vacuum pump, injectors and exhaust manifold, remain on the cylinder head. In this case, the cylinder head can be lifted from the crankcase with all components intact.
1. Remove drive belt. -> 137819 Removing and installing drive belt on 4.8-litre DFI engines - section on "Removing" Service and Repair
2. Remove power-steering pump and air conditioning compressor if necessary.
3. Remove spark plugs. -> 287020 Removing and installing spark plugs on DFI engines - section on "Removing" Service and Repair
4. Remove intake-air distributor. -> 244619 Removing and installing intake-air distributor on DFI engines - section on "Removing" Removal and Replacement
5. Remove fuel distribution pipe. -> 243019 Removing and installing fuel distribution pipe (fuel rail) on DFI engines - section on "Removing" Service and Repair
6. Remove high-pressure pump at cylinder 8. -> 246319 Removing and installing DFI high-pressure pump - section on "Removing" 246319 Removing and installing DFI high-pressure pump
7. Remove vacuum pump -1- at cylinder 4. To do this, loosen the three screws -2-.
Vacuum pump
8. Remove tank vent and line -7-. Remove vent line -5- between oil mist separator and timing-case cover.
Oil mist separator for positive crankcase ventilation 2
9. Remove high-pressure line -2- from cylinder head. To do this, remove union nut -4-.
High-pressure pump on naturally aspirated engine M48/01, 3-piston pump
10. Remove vent line.
10.1. Unscrew fastening screws -1-.
10.2. Unclip vent line -2- from the cable duct and remove it -arrow-.
Removing vent line
11. Remove oil dipstick with guide tube -1-. To do this, loosen two screws -3 and 11- and pull out the guide tube.
Oil guide housing with accessories
12. Detach and remove the coolant hose assembly -2-. Remove coolant pipe -1-. Detach coolant hose from the generator -4-.
Coolant return line on naturally aspirated engine M48/01
Coolant supply line on naturally aspirated engine M48/01
13. Remove heat protection panels on both sides.
Heat protection panels on V8 naturally aspirated engine
14. Remove the generator. Expose the peripheral equipment and unscrew the generator.
14.1. Remove support bracket (crash support) -10- from the generator (two screws) -9-.
Auxiliary units
14.2. Remove fastening screws on the generator -2 and 3-.
Generator
14.3. Carefully remove generator and disconnect B+ cable. To do this, remove nut on the rear of the generator.
15. Remove starter -1-. To do this, remove the screws -2-.
Starter
16. Remove engine wire harness and set it down safely. For details, see -> 975219 Removing and installing engine wire harness - section on "Removing"
Installation position of engine wire harness
Connector overview for engine wire harness
17. Remove exhaust manifold on both sides. To do this, expose cable for oxygen sensor (lambda sensor).
Exhaust manifold on naturally aspirated engine M48/01, cylinders 1 to 4
18. Remove engine carrier with engine mountings on both sides. Then remove the brackets for the auxiliary units. => Left bracket for auxiliary units and engine mounting => Right bracket for auxiliary units and engine mounting
Left bracket for auxiliary units and engine mounting
Right bracket for auxiliary units and engine mounting
19. Remove water pump. -> 195019 Removing and installing coolant pump on DFI engines - section on "Removing" Service and Repair
Coolant pump
20. Disconnect coolant pipe -1 at 9-. To do this, remove the screws -3-.
Coolant guide
21. Pull out intake socket for thermostat -6-. Detach thermostat housing and remove with the coolant pipe fitted. For details, see -> 195819 Removing and installing coolant regulator (thermostat) on DFI engines - section on "Removing" Service and Repair.
Thermostat housing
22. Remove coolant pipe on the right side. -2-
Coolant supply line on naturally aspirated engine M48/01
23. Remove belt tensioner and deflection rollers. To do this, carefully lever off the covers on the rollers and unscrew the components. -1, 2, 3, 4-
Belt drive
24. Unscrew oil pressure sensor -3- with adapter -1- from the crankcase. To do this, remove the screws -4-.
Oil pressure sensor and oil pressure measuring point
25. Remove both cylinder head covers (valve covers). -> 158219 Removing and installing cylinder head cover (valve cover) on 4.8-litre DFI engines - section on "Removing" Removal and Replacement
Valve cover, cylinder bank 5 to 8
WARNING
Risk of damage to the engine and danger of crushing if the engine tips over
- When removing and installing the vibration balancer with the engine removed (engine on assembly support), excessive use of force can cause the assembly mounting to become kinked.
-> The engine must be supported at the oil pan or engine carrier using suitable lifting equipment and a wide wooden block. This applies to all engines and assembly mountings.
26. Loosen screw on vibration balancer by two turns -4 and 3-. To do this, hold a brace brace 9679/1 at the vibration balancer with the help of a second worker. Support the brace on the floor if necessary. A very high torque is required to loosen the screw (more than 800 Nm/592 ftlb.). A long 3/4-inch tool is the best tool to use for this. The engine should be supported to prevent it from tipping over.
Supporting engine (illustration shows V8 4.5-litre engine supported on assembly support)
Pulleys
27. Turn the crankshaft at the vibration balancer so that the staking bore of the vibration balancer is located approx. 45° degrees in front of the lower staking point on the timing-case cover. => Staking bore 45 degrees before TDC
Staking bore 45 degrees before TDC
28. Loosen camshaft controllers and sprockets on the four camshafts by 2 turns. Always counter at the hexagon on the components when doing this. => Sprocket => Camshaft controller
Sprocket
Camshaft controller
29. Remove chain tensioner for timing chain from the timing-case cover. -5-
Chain tensioner
30. Remove vibration balancer.
31. Turn the engine around. The oil pan must be facing upwards.
32. Unscrew oil pan -1-. To do this, remove all the screws -4-. The inserted seal can be reused. It only needs to be replaced if damaged (cracked, worn down, hardened, etc.) or if it is leaking.
Oil pan
33. Detach and remove joint flange on oil pressure control valve. -8, 9 and 10- Disconnect oil level sensor and remove by turning -7-.
Oil guide housing with accessories
34. Remove all oil lines between the oil guide housing and oil pump. => Oil lines on naturally aspirated engine (M48/01) => Oil lines, intake manifold on naturally aspirated engine M48/01
Oil lines on naturally aspirated engine (M48/01)
Oil lines, intake manifold on naturally aspirated engine M48/01
35. Remove all screws between the oil guide housing and crankcase/timing-case cover. -6- Do not forget the four screws at the front.
Oil guide housing with accessories
36. The oil guide housing is sealed with glue. To make it easier to remove, lever off the oil guide housing between the outer flanges on the crankcase and the oil guide housing. => Removing oil guide housing Remove the entire oil guide housing. Remove old sealing ring.
Removing oil guide housing
37. Remove joint flange on vibration balancer -1- at the timing-case cover. To do this, remove the screws -2 and 3-.
Chain tensioner, joint flange
38. Remove all M6 and M8 screws on the timing-case cover => Timing-case cover and lift off timing-case cover. Also remove all the metal seals -2, 3, 4 and 5-.
Timing-case cover
Timing-case cover seals
39. Remove timing chain -1- (mark rolling direction for reinstallation using a felt-tip pen) from all the sprockets and place on a clean surface.
Timing chain and sprockets
40. Remove tensioning rail -4-. Remove threaded peg -1- if necessary.
Tensioning rail
41. Remove U-rail (guide rail) -4-. To do this, remove four M8 screws -5-.
Timing chain and sprockets
42. Carefully slacken the lower tensioning rail for the oil pump chain. Press the tensioning rail back with a small screwdriver until both staking holes between the tensioning rail and guide rail are aligned. => Oil pump tensioning rail
Oil pump tensioning rail
43. Stake tensioning rail for oil pump chain through the hole in the guide rail using a suitable drill bit, drift punch or nail. This slackens the oil pump chain. => Staking tensioning rail for oil pump chain
Staking tensioning rail for oil pump chain
44. Remove guide rail -3-. Guide rail is locked with -6-.
Guide rail
45. Remove oil return line/vent line -1-. To do this, unscrew screws -3- and remove line.
Vent line
46. If the sprockets and camshaft controllers are to be separated from the camshafts, now unscrew the loosened camshaft controllers and sprockets. A friction plate -4- is installed under each camshaft controller. Replace friction plate if it was completely removed.
Camshaft control
47. Slowly and uniformly loosen and unscrew all M6 screws -3 and 5- on the camshaft housings -2, 4 and 6-. The housings are marked E for intake camshaft and A for outlet camshaft. The housings are numbered consecutively by cylinder. The housings are seated very securely in the cylinder head because of a dowel sleeve -1-. Jiggle free using a pliers if necessary. Place on a marked, clean surface.
Camshaft mount, cylinders 5 to 8
48. Remove camshafts -3 and 6- and place on a marked, clean surface.
Camshafts, cylinders 5 to 8
49. Remove valve lifters -1 and 2- and place on a marked, clean surface in such a way that they cannot be mixed up.
Diagram showing how to set down lifters
50. Remove mounting saddle at the front -8-. This hides the cylinder head screws underneath.
51. Remove front M8 screw securing the cylinder head of cylinders 1 to 4 to the crankcase. -3-
Cylinder head 1 to 4
52. Turn the engine so that the cylinder head you want to remove is pointing straight upwards.
53. The injectors can now be removed easily if necessary. For details, see -> 244019 Removing and installing high-pressure fuel injector (DFI) - section on "Removing" 244019 Removing and installing high-pressure fuel injector (DFI)
54. Remove cylinder head screws in the opposite order to the tightening sequence shown => Tightening sequence for cylinder head. Remove cylinder head.
Tightening sequence for cylinder head
55. Remove cylinder head gasket.
56. Remove cylinder head for cylinders 5 to 8 in the same way.
57. Turn the engine around. The oil pump must be facing upwards.
58. Remove chain cover for oil pump -9-. To do this, remove the screws -10-.
Oil pump on naturally aspirated engine M48/01
59. Remove drive pinion for oil pump. Screw is tightened beyond the elastic limit. Use a screwdriver to counter at the oil pump through the bore in the drive pinion. => Countering oil pump pinion
Countering oil pump pinion
60. Remove oil pump pinion with chain and crankshaft pinion. => Oil pump chain
Oil pump chain
61. Unscrew oil pump -1-. To do this, remove the screws -8-. Pull oil pump out at the point where the pipe engages at the rear with the oil plate. When doing so, make sure that the locking lug does not break off. Swivel oil pump out and up.
62. Unscrew oil plate/oil guide.
Oil guide (oil plate)
63. Remove lower part of crankcase.
Lower part of crankcase
63.1. First unscrew the four M8 screws on the output side. -8 and 9-
63.2. Unscrew outer M8 cross bolt connection in the opposite order to the tightening sequence.
Tightening sequence for securing lower part of crankcase to upper part of crankcase (cross bolt connection)
63.3. Unscrew M10 and M11 thrust-bearing screws in the opposite order to the tightening sequence. Start with the outer M10 screws first.
Tightening sequence for thrust-bearing screws
63.4. Lift off lower part of crankcase. Get a second person to help if necessary. Remove old sealing ring. Remove bearing shells if necessary and mark them.
64. Secure crankshaft at the centre using a holding bridge holding bridge 9677/1. Tighten screws slightly. -1-
Crankshaft secured
65. Loosen connecting rod bolts -6- and take off connecting rod cap -5-. Push piston in question out of the crankcase using a wooden rod. Hold it in your other hand or get another person to help. Fit connecting rod cap hand-tight to the connecting rod again using the old screws and set down after marking according to the relevant cylinder. The connecting rod bolts must be replaced with new ones during reinstallation. The connecting rods are cracked and the connecting rod code is facing the exhaust side. The combustion chamber recess on the piston is facing the injector.
Piston, connecting rod
66. Remove all pistons in the same way.
67. (If you have not already done so) turn the engine so that the crankshaft is at the top.
WARNING
The crankshaft is heavy!
- There is a danger of hands being crushed when inserting the crankshaft.
-> Hold the very outside of the crankshaft.
-> Wear gloves.
68. After removing all the pistons, remove the crankshaft -1- (remove holding bridge) and place on a clean surface.
Crankshaft
69. Remove all bearing shells -5 and 6- and thrust washers -4- if necessary. Mark the bearing shells and set them down.
70. Remove oil spray jets -6-. To do this, loosen the screws -7-.
Upper part of crankcase
71. Remove coolant guide -9-. Remove seals -10-.
Coolant guide