1998 BMW 540i Ac system

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Camshaft Timing Chain
lnstall vibration damper mounting bolts. Note hub locating
dowel (arrow).
Tightening torque
Vibration damper to crankshaft hub
(ME) 22 Nm (16 ft-lb)
- Installation is reverse of removal noting the following:
Installing drive belts. See 020 Maintenance.
Install cooling fan. See 170 Radiator and Cooling Sys-
tem.
Crankshaft oil seal, replacing
(M52 TU and M54 engines)
The crankshafl front seal IS located in the lower timing cover,
behind the
vibrat~on damper.
- Disconnect negative (-) cable from battery.
Disconnecting the battery may erase fault
code(s) storedin
control module memoy Checlc for fault codes using spe-
cial
BMW diagnostic equipment.
Prior to disconnecting the battery, read the battery dis-
connection cautions given in
001 General Cautions
and Warnings.
- Remove splash guard from beneath engine
- Remove engine cooling fan assembly. See 170 Radiator
and Cooling System.
NOTE- Cooling fan nut
(32 mm wrench) has left-hand threads.
- Remove drive belts. See 020 Maintenance
NOTE-
Mark direction of belt rotation if reusing belt.
- Install crankshaft holding tool (BMW special tool 11 8 19011 1
8 200). Make sure tool locks into place in openings in damper
assembly. While counterholding crankshafl with special tool,
remove crankshaft center bolt.
CAUTIOI\C
Do not use flywheel locling tool to hold crankshaft station-
ary to loosen or tighten
cranl(shaft hub center bolt. Use
only the special tools specified, or equivalent hub holding
tool.
Use care when removing
damper/hub assembly, as ~t is
easy to damage the radiator

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Camshaft Timing chain]
4 Coat new seal with oil and position in timing chain cover. Use
BMW special tool 11
3 280 and crankshaft center bolt to draw
seal in flush with timing case cover.
- Align vibration damper assembly with keyway and tap into
place. Insert new center bolt with washer.
CA
UTIOG
Inspect woodruff key for damage before installing hub
assembly.
- Install crankshaft holding tool malting sure tool locks into
place in openings in damper assembly. While counterholding
cranltshaft, tighten crankshaft center bolt.
- Attach special tools 11 8 20011 1 8 190 to damper assembly.
Counterhold damper with 11 8 190 while tightening center
bolt.
Tightening
torque
Vibration damper hub to crankshaft 410 Nm (302 it-ib)
- Installation is reverse of removal noting the following:
Install drive belts. See 020 Maintenance.
Install cooling fan. See 170 Radiator and Cooling Sys-
tem.
Crankshaft oil seal, replacing
(M62 and M62 TU engines)
- Disconnect negative (-) cable from battery
CAUTIOG
Disconnecting the battery may erase fault code(s) storedin
control module memory. Check for fault codes using spe-
cial BMW diagnostic equipment.
* Prior to disconnecting the battery, read the battery dis-
connection cautions in
001 General cautions and
warnings.
- Remove splash guard from beneath engine
- Remove engine cooling fan assembly. See 170 Radiator
and Cooling System.
NOTE
-
Cooling fan nut (32 mm wrench) has left-hand threads.
- Remove drive belts. See 020 Maintenance.
NOTE-
Marlc direction of belt rotation if reusing belt.

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I Camshaft Timing Chain
Mark 0" location on socket (arrow). Tighten hub bolt in four
stages.
Tightening torque Vibration damper
hub to cranlrshaft
Stage 1 100 Nm (74 it-lb)
Stage
2 60" Torque angle
Stage
3 60" Torque angle
Stage
4 30" Torque angle
- install vibration damper and mounting bolts
NOTE-
Male sure to align vibration damper with locating dowel pin
in hub.
Tightening torque Vibration damper to
cranltshait hub (ME) 22 Nm (16 ft-lb)
- Install drive belts. See 020 Maintenance.
- Install cooling fan. See 170 Radiator and Cooling System.
- Replace under engine splash shield, then reconnect nega-
tive battery cable.
!/ANBS CONTROL UNIT AND
TIMING CHAIN (M52 ENGINE)
VANOS control unit, removing (M52 engine)
NOTE-
Special BMW service tools are required to remove and in-
stall the
VANOS control unit. Read the procedure through
before starting the job.
If the camshafts are notproperly timed, the pistons can
contact the valves.
- Disconnect negative (-) cable from battery.
CAUTION-
Disconnecting the battery may erase fault code(s) stored in
control module memory. Prior to disconnecting the
battev,
check for fault codes using special BMW diagnostic equip-
ment.
* Prior to disconnecting the battery, read the battery dis-
connection cautions given in
001 General Cautions
and Warnings.

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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.

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11 7-20
Camshaft Timing Chain
4 lnstall BMW special tool 1 I 5 490 on exhaust camshaft.
- Insert the helical-toothed splined shafl (arrow) into the heli-
cal-toothed sprocket while rotating gears and chain counter-
clockwise with special tool.
CAUTION- Ensure
that the first available tooth engages. It is important
that the exhaust camshaft sprocket be turned only the mini-
mum amount necessary to engage the gear cup. If this pro-
cedure is done
incorrectlq: the VANOS system may not fully
function.
- Install and tighten down VANOS control unit fasteners
Tightening torques
VANOS control unit to cylinder head
M6 nuts 10 Nm (89 in-lb)
M8 bolts 22 Nrn (17 ft-lbj
- Press down on secondary timing chain tensioner and remove
lock tool.
Remove primary timing chain tensioner
(arrow)
CAUTION-
Timing chain tensioner is under spring tension.
lnstall adjustable primary chain tensioner
(BMW special tool
11 4 220) and preload timing chain by tightening to 1.3 Nm
(I I in-lb).

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Camshaft Timing Chain/ - - - - - - . - - . - .
Tighten exhaust camshaft sprocket mounting bolts (arrows)
alternately in two stages.
Tightening torques
Secondary timing chain sprocltets to camshafts
Stage
1
Stage 2
5 Nm (44 in-lb)
22 Nm (17 ft-lb)
- Remove crankshaft locking tool and camshaft locking tool
set.
- install camshaft gear bolt access plugs using new sealing
washers and tighten.
- Remove timing chain tensioning tool from side of cylinder
head. Install primary chain tensioner with new sealing wash-
er and tighten.
Tightening torques
Access plugs to VANOS control unit 50 Nm (37 ft-lb)
Primary timing chain tensioner
plug to 70 Nm (52 ft-lb)
tensioner sleeve
- Check adjustment VANOS system, see VANOS timing,
checking and adjusting
(M52 engine).

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Camshaft Timing Chain
VANOS timing, checking and adjusting
(M52 engine)
NOTE-
* Special BMW service tools are required to remove and in-
stall the VANOS control unit. Read the procedure through
before starting the job.
If the camshafts are not properly timed, the pistons can
contact the valves.
- Disconnect negative (-) cable from battery.
CAUTIOG Disconnecting the battery may erase
faultcode(s) storedin
control module memory. Prior to disconnecting the battery,
checlc for fault codes using special BMW diagnostic equip-
ment.
Prior to disconnecting the battery, read the battery dis-
connection cautions given in
001 General Cautions
and Warnings.
- Remove viscous clutch cooling fan. See 170 Radiator and
Cooling
System.
CAUTIOG The radiator cooling fan nut
(32 mm wrench) has left-hand
threads.
4 Remove ignition coils:
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.

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Camshaft Timing Chain Timing chains, removing
(M52 engine)
Camshaft timing chain removal on M52 engines requires en-
gine oil pan removal.
Special
BMW sewice tools are needed for timing chain re-
moval and installation procedures. The special tools assure
propertiming of thevalvetrain. Precise marks to
setthe timing
on the camshafts are not provided for reassembly. Read the
procedures through before beginning the job.
NOTE-
If the camshafts are not properly timed, the pistons can con-
tact the valves.
- Remove VANOS control unit. See VANOS control unit, re-
moving (M52 engine).
- Remove radiator cooling fan and shroud. See 170 Radiator
and Cooling System.
- Drain cooling system. See 170 Radiator and Cooling Sys-
tem.
- Remove coolant hoses from thermostat housing and remove
thermostat housing from front of cylinder head.
- Loosen bolts for coolant pump pulley.
- Remove drive belts for alternator and AIC compressor. See
020 Maintenance.
- Remove coolant pump pulley.
Remove drive belt tensioner mounting bolts (arrows) and re-
move tensioner from front of engine.
- Remove engine speed sensor from lower timing chain cover.