Part 1
Disassembling and assembling engine
Preliminary work for disassembling engine
1. Remove engine.
2. Remove transmission.
3. Remove rear silencers and catalytic converters.
Tiptronic transmission:
- Detach torque converter housing.
- Removing drive plate for converter.
Manual transmission:
- Remove clutch.
- Remove dual-mass flywheel.
Component overview - engine
Information
The overview graphics are shown schematically and may be different to how the components actually look.
Intake system, belt drive
Peripheral engine component 1
^ 1 - Intake distributor
^ 2 - Belt drive
^ 3 - Belt guide and belt tensioner
Engine - lubrication
Engine - lubrication
^ 4 - Oil pumps, heat exchanger, coolant guide housing
^ 5 - Oil pan, oil separator
Cylinder head, crankcase
Cylinder head, crankcase
^ 6 - Cylinder-head cover, camshafts, flat-base tappet housing, cylinder head
^ 7 - Cylinder head, bucket tappets
^ 8 - Crankcase halves
Crank drive, pistons
Crank drive, pistons
^ 9 - Pistons, connecting rods
^ 10 - Bearing housing with intermediate shaft
^ 11 - Bearing housing halves with crankshaft
Disassembling engine down to crankcase
Caution
Risk of damage due to particles of dirt.
^ Danger of material damage due to blocked oil bores/oil ducts.
-> Absolute cleanliness is essential when working on the engine.
-> Lay removed engine parts on a clean base and make sure to cover them.
-> Use the cover for dust protection when fitting the engine NR.165 on the engine assembly support.
Warning
Caustic fluid
^ Danger of chemical burns
-> Avoid contact with caustic fluid.
-> Wear personal protective gear.
-> Ensure that there is good ventilation.
-> If you do come into contact, wash off immediately with plenty of warm water and contact a doctor if necessary.
Warning
Pentosin is hazardous to health
^ Danger of material damage and injury
-> Wear protective gloves and goggles.
-> If the fluid gets into your eyes or on your skin, rinse or wash immediately with water.
-> Collect emerging Pentosin. Clean hoses which come into contact with Pentosin thoroughly.
-> Use caps to protect the wiring against soiling and damage.
Information
^ The bearing housing remains screwed to the retaining device when the bearing housing and intermediate shaft are disassembled.
1. Engine support 9589 must be secured to the crankcase using special tool mounting elements 9590. Refit engine with support on the engine assembly support.
Engine support
2. Drain engine oil. Unscrew the oil drain plug (hexagon socket a/f 8).
Oil drain plug
3. Remove engine carrier. Unscrew 4 M10 collar nuts and 1 M6 x 20 Torx screw.
Engine carrier
4. Undo 3 M8 x 12 fastening screws on the belt pulley for the servo pump (do not remove).
5. Remove drive belt. Mark the running direction with a colored pen, turn the tensioning roller (a/f 24) clockwise, hold still and simultaneously remove the belt from the drive pulleys. Check the belt for damage, replace if necessary.
Belt tensioner
6. Only for Tiptronic: remove guide for drive belt, to do this, unscrew two M6 x 20 Torx screws.
7. Unclip hose assembly on the intake distributor, cylinder side 1 - 3:
Vacuum lines
8. Unplug crankcase ventilation line on pre-separator, cylinder 4-6.
View of engine, side 4-6
9. Remove shields for ignition coils on the left and the right, unscrew 2 M6 x 16 fastening screws.
Ignition coil shield
10. Disconnect electric plug connections (engine wire harness) on engine and unclip wire harness on the fuel collection pipes.
View of engine, side 1-3
^ Three injection valve plugs per cylinder side -1-
^ Three ignition coil plugs per cylinder side -2-
^ Two plugs for camshaft adjustment hydraulic valves, two for valve lift adjustment hydraulic valves -3-
^ Plug for engine coolant temperature sensor, two plugs for oil pressure sensor on cylinder head cover 4 - 6 -4-
^ Two hall sender connectors
^ Plugs for speed sender
^ Plug for electric switch-over valve (intake distributor 1-3)
^ Ground cable for front face of cylinder 4-6 (one M6 x 12 Torx screw)
^ Plug for engine compartment temperature sensor (intake distributor 4-6)
11. Unclip fuel ring pipe on the engine eyelet and unscrew two M6 x 16 Torx screws, remove engine eyelet.
12. Detach holder for the throttle body on the servo pump. To do so, unscrew an M6 hexagon nut. Unplug cable plug for potentiometer and line for crankcase venting.
13. Undo holder for servo supply tank on intake distributor 4-6.
14. Only for 3.6l engine: Remove the relevant six M6 x 35 (micro-self-locking) fastening screws for the intake distributor on the intake pipe supports on the left and the right. Pull off one vacuum line and remove the intake distributor completely.
3.6l intake distributor
15. Only for 3.6l engine: Remove intake pipe support. Unscrew four M6 x 35 screws, unscrew one M6 x 12 screw for ground strap on cylinder bank 4 - 6. Take off intake pipe support, seal intake openings on cylinder head (e.g. with adhesive tape).
Intake pipe support
16. Only for 3.8l engine: Unscrew the four M6 x 35 Torx screws. Completely remove the intake distributor. Seal intake openings on cylinder head (e.g. with adhesive tape).
Intake distributor screw connection
17. Remove belt pulley from servo pump. Unscrew three fastening screws and remove belt pulley.
18. Remove generator. Undo the fastening screw on the deflection roller -1- and unscrew approx. three turns. Using an aluminum mandrel, tap lightly on the screw head to undo the pilot bushing in the generator swivel arm. Unscrew the screw and remove with the deflection roller. Unscrew the second screw -2- and carefully take out the generator.
Generator
19. Lift the generator out of the bracket and disconnect the two electric connecting lines -arrows-.
Electric connections on generator
20. Remove mount for the coolant vent line. Unscrew one M6 x 16 (micro-self-locking), remove mount, replace screw.
21. Unplug all vent lines for oil mist collector.
Oil mist collector - line connections for 3.8 l engine
22. Unscrew the two M6 x 20 Torx screws on the 3.8 l oil mist collector mount and pull off collector. Replace two O-rings during installation. The screws tighten the secondary air line on cylinder head 4-6 at the same time.
Threaded joint for 3.8 l oil mist collector
23. The oil mist collector on a 3.6 l engine is removed in the same way as the 996 unit.
Oil mist collector on 3.6 l engine
24. Unscrew one fastening screw for the wire harness guide on the bracket for the secondary air pump -1- and unclip the guide -2- on the bracket -arrow-.
Wire harness on secondary air pump
25. Remove the secondary air pump. Unplug cable plug, unscrew three M6 x 20 Torx screws on the bracket -1- and completely take out the pump with bracket and line. Use new seals when installing.
Secondary air pump with bracket
26. Release the wire harness on the holder before the heat exchanger. Then unscrew the plastic holder.
Wire harness on the heat exchanger
27. Undo the wire harness on the center of engine (connections to starter) -arrow- and unclip on the heat exchanger -1-. Unplug cable plug for knock sensors -2- and oil-level sensor. Then completely remove the engine wire harness.
Releasing wire harness
28. Remove the oil filler neck. Unscrew 2 M6 x 16 Torx screws (micro-self-locking), pull out oil filler neck, check the O-ring and replace if necessary.
Oil filler neck
29. Remove oil/water heat exchanger. Unscrew the four inner M6 x 16 Torx screws, take off heat exchanger.
Replace O-rings during installation.
30. Remove hydraulic pump with servo line and supply tank. Undo servo line (a/f 16) -1-, counter on large hexagon when doing this (a/f 27). Unscrew four Torx screws (3 M8 x 30 at the front -arrows-, one M8 x 12 at the back), take the servo pump with line and supply tank out of the bracket.
Servo pump
31. Remove bracket for servo pump. Unscrew 4 M8 x 35 Torx screws, remove bracket.
Bracket for servo pump
32. Remove one M8 x 60 screw for deflection roller -1- and six M6 x 20 Torx screws for closure cap -2- with bleeder lines for coolant system.
Deflection roller and closure cap for coolant
33. Only in manual transmissions: Remove the starter. Unscrew two M10 x 35 Torx screws -1-, take off starter -2-.
Starter
34. Remove oil-level sensor (a/f 19), remove knock sensor, to do this, mark the installation position with a paint marker, then unscrew one M8 x 35 Torx screw each and take off the sensors.
35. Remove canister for additional volumes of crankcase venting to the cylinder heads 1-3 and 4-6. Unscrew two M6 x 25 Torx screws each, take off canister. Use new O-rings when installing.
36. Remove the holder for the main muffler on the left and right. Unscrew two M8 x 30 Torx screws each on the intake side and two M8 x 25 each on the exhaust side and take off mount.
NSD mount
37. Remove mount and sealing cap for hydraulic valves for camshaft adjustment -2-. Unscrew two M6 x 20 Torx screws each, take off mount and sealing cap.
Hydraulic valves for camshaft adjustment
38. Remove three ignition coils per cylinder side -1-. Unscrew 12 M6 x 25 Torx screws, pull off ignition coils.
39. Remove six spark plugs. Use only approved tool spark plug socket wrench 14 from Snap-On (in case ceramic body breaks).
40. Pull off hydraulic valves for camshaft and valve lift adjustment. To do this, the special tool relay puller 9235 can be used. Pull the oil strainer for the camshaft adjustment valve out of the valve bore -1- with a magnet, replace the oil strainer.
Oil strainer hydraulic valve NVS