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I Cylinder Head and Valvetrain
- Remove adjustable primary timing chain tensioner tool and
reinstall primary chain tensioner cylinder to cylinder head.
Tightening torque
Primary chain tensioner cylinder
to 70 Nm (52 ft-lb)
cylinder head
- Remove flywheel locking tool from crankcase. Replace spe-
cial tool bore sealing plug.
- Remove camshaft locking tools from cylinder head
Install intake camshaft cover and cylinder head cover.
Check for correct seating of half-moon seals (A) in back of
cylinder head cover.
Use a small amount of Three Bond
8 1209 or equivalent
sealing compound at corners
(B) of half-moon cutouts.
Seat gasket and seal corners at VANOS unit with Three
Bond
@ 1209.
Tightening torque Cylinder head cover to cylinder head
(M6) 10 Nm (89 in-lb)
- Installation of the remaininq parts is reverse or removal, not- -
ing the following:
Change engine
011 and f~lter as descr~bed in 020 Mainte-
nance.
Reconnect battery.
To prevent damaging the engine electronic systems, install
all ground wire previously removed, including the ground
wires for the ignition coils.
Tightening torque
-
Radiator cooling fan to coolant pump 40 Nm
(30 ft-ib)
Spark plug to cylinder head
25 Nm (18 ft-ib)
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Cylinder Head and valvetrain1
Camshaft removal and installation
(M62 engine)
Camshafts, removing (M62 engine)
Special
BMW service tools should always be used to remove
and install the camshafts. Removal of the camshafts without
the special tools can result in personal injury and lor cylinder
head damage.
NOTE-
Cylinder bank 1-4 is referred to as the right cylinder bank
and is located on the passenger side. Cylinder bank 5-8 is
referred to as the left cylinder bank and is located on the driv-
er's side.
WARNING-
Allow enqine to cool before beqinninq this procedure. 1
- Disconnect negative (-) cable from battery.
CAUTION-
Prior to disconnecting the battery, read the battery discon-
nection cautions
in 001 General Cautions and Warnings.
- Dra~n coolant. See 170 Radiator and Cooling System.
Remove plastic engine covers:
Press down on locking pins (arrows) and remove top
cover.
Pry out
trlm caps (A) from covers.
Remove fasteners from beneath
trlm caps and remove
side covers.
4 Remove left and right interior ventilation filter housing (lefl
side shown):
Release locking tabs
(A) or locking strap (early models,
not shown).
Rotate duct inward (arrow) to disconnect.
- Release spring lock (6) to unloclc ventilation housing.
Disconnect electrical harness from hood switch
(C).
Release locking clip and remove ventilation filter cover (0).
Remove filter housing.
Removal of right side ventilation duct is similar.
Page 221 of 1002
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Cylinder Head and valvetrain1
While counter holding camshaft, remove exhaust camshaft
sprocket bolts
(arrows) from left cylinder head. Remove
sprocltets with chain.
< While counter holding camshaft, remove exhaust camshaft
sprocket bolts
(arrows) from right cylinder head. Remove
sprocltets with chain.
4 Use BMW special tool 11 3 430 to rotate camshaft into disas-
sembly position.
4 Loosen camshaft bearing caps nuts in correct sequence
(1-10) (left cylinder head shown).
NOTE -
Keep camshaft bearing caps in order. Used caps must not be
interchanged.
- Remove exhaust camshaft by repeating process.
0 Remove camshafts from cylinder head.
- Repeat camshaft removal process for right cylinder head.
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11 6-55
Cvlinder Head and valvetrain1
4 Remove cylinder head cover sealing gasltets from left cylin-
der head cover. Install BMW special tool 11 1 412 into gasket
groove of cylinder head cover.
Install left cylinder head cover. Fit cylinder head cover re-
taining nuts to cylinder head cover studs at cylinders
5 and
6 (first two cylinders on left side cylinder bank).
* Tighten nuts uniformly in 'I? turn steps.
NOTE-
BMW special tool 11 1 4 12presses upper timing chain cover
to level of cylinder head.
Tightening torque Cylinder head cover
nuts 10 Nm (7.5 it-lb)
- Tighten left upper timing chain cover retaining bolts in two
passes.
Tightening torque
Timing chain cover to head
10 Nm (7.5 ft-lb)
- Remove cylinder head covers and remove BMW special
tools 11 4 41 11412 from cylinder head covers.
- Fit new gasket to cylinder head cover without strain.
- Apply Three Bond@ 1209 sealant to joints between cylinder
head and timing cover.
4 Malte sure half-moon cutouts (A) at rear of cylinder heads fit
correctly to cylinder head sealing surface. Apply Three
Bond@ 1209 sealant at corners of half-moon cutouts (B).
- Remainder of installation is reverse of removal.
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1 16-56
Cylinder Head and Valvetrain
This section covers valve removal and reconditioning, includ-
ing valve guides, seats, springs, and valve stem oil seals.
Valves, leak test
To test the valves for leakage, the cylinder head must be dis-
assembled with camshafts and camshaft carriers removed.
With valve assemblies and spark plugs installed, place the
cylinder head on a workbench with the combustion chamber
facing upward. Fill each combustion chamber with a thin non-
flammable liquid. After fifteen minutes,
check the level of the
fluid. If the fluid level in any cylinder drops, that cylinder is not
sealing properly.
Valves, removing and installing
- Remove cylinder head as described in 113 Cylinder Head
Removal and Installation.
CAUTIOI\C
(M52 TU/M54 engines only) Do not let the hydraulic lifters
fall out as the camshaft carrier is removed. Special suction
cups are available from
BMW to hold the hydraulic lifters in
place during carrier removal.
* Hydraulic cam lifters should be stored m an uprfght po-
sition. If necessary, use a magnetic tool to
aidin remov-
al of the lifters.
- Remove valves using a valve spring compressor.
CAUTIOI\C
Label each valve assembly as it is removed so it can be in-
stalled in its original position.
-
- Remove and discard valve stem oil seals from valve guides.
See Valve stem oil seals later in this section.
- Valve installation is reverse of removal. Remove carbon de- - -
posits from the valves using a wire brush or wire wheel. -
-
Valve specifications are listed in Table c. Valve specifica-
tions.
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Table d. Valve guide specifications
Specifications
All engines (1997-2002)
Valve guide wear, maximum 0.5 mrn (0.020 in)
(valve tilt clearance
measured
with new valve)
Valve guide inside diameter,
installed
(tolerance per IS0 allowance H7)
Standard 6.0 mm (0.236 in)
Oversize
1 6.1 mrn (0.240 in)
Oversize 2 6.2
mm (0.244 in)
Valve stem oil seals
The purpose of the valve stem oil seal is to prevent excess oil
from entering the combustion chamber. The sign of faulty
valve stem oil seals is excessive oil consumption and smoke
from the exhaust immediately after starting and during decel-
eration.
NOTE-
Valve stem oil seals should not be reused. If valves are re-
moved, new valve stem oil seals should be installed.
Valve stem oil seal replacement requires that the cylinder
head be disassembled and the valves removed as described
above under Valves, removing and installing.
NOTE-
BMW special tools are available to remove the valve stem oil
seals. As an alternative, standard valve seal removal tools
are available from most automotive parts stores.
Lubricate new seal and install using hand pressure only. Be
sure to install valve spring
seat(s) before installing seal.
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1 17-2
Camshaft Timing Chain
This repair group covers timing chain and VANOS repair
information for the following engines:
M52 (Single VANOS 6-cylinder engine)
M52
TU and M54 (Double VANOS engines)
M62 (Non VANOS
V-8 engine)
NOTE-
The M62 TU V-8 engine with VANOS Variable Camshaft
Timing repair information is not included.
NOTE-
See 100 Engine General for engine code and application
information.
Worn timing chains and sprocltets can lead to noisy operation
and erratic valve timing. Afaulty tensionercan also cause tim-
ing chain noises.
For specific repair procedures, refer to the appropriate repair
group:
020 Maintenance
113 Cylinder Head Removal and Installation
119 Lubrication System
121 Ignition System
170 Radiator and Cooling System
Special tools
Special BMW service tools are needed to perform the service
and repairs procedures covered in this repair group. Many of
these tools are expensive and only available through an au-
thorized BMW dealer. Be sure to read each procedure thor-
oughly before starting a job to determine which special tools
will be necessary.
In addition, Double VANOS system diagnosis can only be
carried out by using BMW specific electronic scan tools, such
as BMW
DISplus, MoDiC or equivalent.
4 Torque wrench wl flex extension
(Tool No. BMW 00
9 250)
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Camshaft Timina chain1
- Remove viscous clutch cooling fan. See 170 Radiator and
Cooling
System.
CA UTlOEIC
The radiator cooling fan nut (32mm wrench) has left- hand
threads.
.
< Remove engine trim covers:
Pry out plastic trim caps (arrows).
. Remove cover fasteners and covers.
4 Remove ignition coils:
0 Disconnect ignition coil electrical harness connectors
Remove
coil mounting fasteners and remove coils.
Remove spark plugs.
NOTE-
Make note of ignition coil ground strap locations.
Disconnect VANOS electrical harness connector
(A) and oil
line fitting
(B) from VANOS control unit.
NOTE-
Wrap the VANOS oil line fitting with a shop rag to absorb
leaking oil.
- Disconnect cranltcase breather by squeezing at arrows,
- Remove cylinder cover mounting fasteners and remove
cylinder head cover.
NOTE-
The cylinder head cover mounting bolt insulators and gas.
kets should be reinstalled in their original positions. Make
note of their arrangement during removal.