1998 BMW 528i Air

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11 6-42
/ Cvlinder Head and Valvetrain
4 Using crankshaft center bolt, rotate engine clockwise one
complete rotation until the first cylinder is at TDC.
4 Confirm TDC position. Lobes of camshafts for cylinder head
1-4 (passengers side) should point up (arrows).
4 Remove timing chain tensioner (arrow) from right side upper
timing chain cover.
- Remove secondary air injection pipes in front of upper timing
chain covers.
- Remove left and right coolant hoses from coolant pump
housing.
- Detach dipsticlc tube from upper right timing cover,

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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 Timing Chain
4 Camshaft locking tool set, 6-cylinder
(Tool No. BMW
11 3 240)
- 4 Crankshaft seal installation bushing. 6-cylinde~
4 Secondary chain tensioner locking pin set. 6-cylinder
(Tool No.
BMW 11 3 290)
11 3292
4 Secondary chain tensioner loclting pin, V-8
(Tool No. BMW 11 3 310)
4 Air line fitting
(Tool No. BMW
11 3 450)
4 Protractor
(Tool No. BMW
11 3 460)

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1 17-24
I Camshaft Timing Chain
4 Remove banjo bolt from VANOS unit oil feed line and install
BMW special tool 11 3 450.
NOTE-
Oil will drain from oil feed line.
- Connect compressed air line (with pressure set to 2-8 bar or
30-1 10 psi.) to air fitting.
4 Measure gap (A) between secondary timing chain tensioner
and
intake camshaft sensor wheel. Make note of distance.
4 Connect cable test (BMW special tool 11 6 410) to VANOS
connector. Connect positive clip to positive battery terminal.
- Connect negative clip to battery negative terminal.
CAUTION-
Reversing terminals on special tool will damage diode on
VANOS solenoid valve.

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-
Camshaft Timing Chain -. -
Measure gap (B) between secondary timing chain tensioner
and intake camshaft sensor wheel. Make note of distance.
To determine VANOS control travel:
Distance
I3 - distance A = a minimum of 8.5 mm
CAUTION-
If the adjustment travel is less than 8.5 mm the VANOS ad-
justment unit must be removed and readjusted. See
VANOS
control unit, removing (M52 engine)
and VANOS con-
trol unit, installing
(M52 engine).
Remove special tools:
Cranltshaft locking tool.
Camshaft
loclting tool set.
Air fitting.
* VANOS cable adaptor.
- Install VANOS oil line with new seal
- Install oil baffle cover above intake camshaft.
- Install cylinder head cover mounting studs to rear of head.
- Install cylinder head cover,
Tightening
torques
Cylinder head cover 10 Nrn (89 in-lb)
VANOS oil line
32 Nm (24 R-lb)
VANOS solenoid to control unit 30 Nrn (22 ft-lb)
- Installation of remaining parts is reverse of removal.

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1 17-34
1 Camshaft Timing Chain
DOUBLE VAMOS SYSTEM
(M52 TU AND M54 ENGINES)
Double VANOS system function
The M52TU and M54 6-cylinder engines are equipped with a
Double VANOS system that varies intake and exhaust cam-
shaft timing.
The main components of the Double VANOS system are:
lntalte and exhaust camshafts with helical spline inserts.
Camshaft sprockets with adjustable gears.
VANOS actuators (two position piston housing with
inter-
nallexternal helical spline cup).
Three-way solenoid switching valves.
Camshaft position impulse wheels.
Hall effect camshaft position sensors.
Camshaft position
IS varied based on engine rpm, throttle po-
sition signal, intake air and coolant temperature.

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Camshaft Timing Chain
VANOS control unit, removing
(M52 TU and M54 engines)
This procedure includes removal of the Double VANOS con-
trol unit.
NOTE-
If the Double VANOS control unit is being replaced, camshaft
timing must be checked. This procedure requires multiple
special tools. Be sure to read the procedures through before
beginning the repair.
- Working inside luggage compartment, disconnect negative
(-) battery cable.
Prior to disconnecting the
batteg read the battery discon-
nection cautions given in
001 General Cautions and
Remove engine cooling fan assembly. See 170 Radiator
and Cooling System.
Remove engine trim covers.
Pry out plastic trim caps (arrows).
Remove cover fasteners, oil filler cap, and covers.
Remove ignition coils:
Disconnect ignition coil electrical harness connectors.
Remove coil mounting fasteners and coils.
NOTE-
Make note of ignition coil ground strap locations.
Remove spark plugs,

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11 7-39
Camshaft Timing Chain
4 Cover oil hole in VANOS control unit (arrow) with shop towel
to capture oil which will spray when compressed air line is
connected.
- Connect compressed air line to air fitting. Apply air pressure
set to
2 - 8 bar (30 - 110 psi).
4 With compressed air line connected, turn engine clocltwise
using crankshaft center bolt at least two rotations, until cylin-
der
1 is at (TDC) position (intake and exhaust carnshafl lobes
as shown arrows).
Do not rotate engine
countercloclwise to reach the top dead
centerposition. Instead, complete another two complete
Remove sealing plug from bore under starter. Lock
crank-
shafl in TDC position with BMW special tool 11 2 300
(arrow).
-
4 Unscrew and remove threaded studs (arrows) at rear of
cylinder head.