Part 2
Disassembling V8 4.8-liter DFI engine (Continued)
29. 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
30. Remove both cylinder head covers (valve covers).
Valve cover, cylinder bank 5 to 8
Supporting engine (illustration shows V8 4.5-liter engine supported on assembly support)
31. Loosen screw for 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.
Pulleys
32. 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
33. 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
34. Remove chain tensioner for timing chain from the timing-case cover. -5-
Chain tensioner
35. Remove vibration balancer.
36. Turn the engine around. The oil pan must be facing upwards.
37. 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
38. 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
39. Remove all oil lines between the oil guide housing and oil pump.
Oil lines on turbo engine (M48/51)
Oil lines, intake manifold on turbo engine M48/51
40. 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
41. 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. Remove the entire oil guide housing. Remove old sealing ring.
Removing oil guide housing
42. 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
43. Remove all M6 and M8 screws on the timing-case cover and lift off the timing-case cover. Also remove all the metal seals -2, 3, 4 and 5-.
Timing-case cover
Timing-case cover seals
44. 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
45. Remove tensioning rail -4-. Remove threaded peg -1- if necessary.
Tensioning rail
46. Remove U-rail (guide rail) -4-. To do this, remove four M8 screws -5-.
Timing chain and sprockets
47. 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
48. 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
49. Remove guide rail -3-. Guide rail is locked with -6-.
Guide rail
50. Remove oil return line/vent line -1-. To do this, unscrew screws -3- and remove the line.
Vent line
51. 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
52. Slowly and uniformly loosen and then unscrew all M6 screws -3 and 5- in 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
53. Remove camshafts -3 and 6- and place on a marked, clean surface.
Camshafts, cylinders 5 to 8
54. 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
55. Remove mounting saddle at the front -8-. This hides the cylinder head screws underneath.
56. Remove front M8 screw securing the cylinder head of cylinders 1 to 4 to the crankcase. -3-
Cylinder head 1 to 4
57. Turn the engine so that the cylinder head you want to remove is pointing straight upwards.
58. The injectors can now be removed easily if necessary.
59. Remove cylinder head screws in the opposite order to the tightening sequence shown. Remove cylinder head.
Tightening sequence for cylinder head
60. Remove cylinder head gasket.
61. Remove cylinder head for cylinders 5 to 8 in the same way.
62. Turn the engine around. The oil pump must be facing upwards.
63. Remove chain cover for oil pump -9-. To do this, remove the screws -10-.
Oil pump on turbo engine M48/51 with oil extraction stage
64. 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
65. Remove oil pump pinion with chain and crankshaft pinion.
Oil pump chain
66. 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.
67. Unscrew oil plate/oil guide.
Oil guide (oil plate)
68. Remove lower part of crankcase.
Lower part of crankcase
68.1. First unscrew the four M8 screws on the output side. -8 and 9-
68.2. 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)
68.3. 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
68.4. 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.
69. Secure crankshaft at the center using a holding bridge holding bridge 9677/1. Tighten screws slightly. -1-
Crankshaft secured
70. 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
71. Remove all pistons in the same way.
72. (If you have not already done so) turn the engine so that the crankshaft is at the top.
73. After removing all the pistons, remove the crankshaft -1- (remove holding bridge) and place on a clean surface.
Crankshaft
74. Remove all the bearing shells -5 and 6- and thrust washers -4- if necessary. Mark the bearing shells and set them down.
75. Remove oil spray jets -6-. To do this, loosen the screws -7-.
Upper part of crankcase
76. Remove coolant guide -9-. Remove seals -10-.
Coolant guide