1998 BMW 540i Start

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Camshaft Timing Chain -- - -1
Q Remove oil baffle cover
from intake
camshaft
Remove front engine lifting bracket fasteners (arrows
A) and
remove bracket.
- Remove cable duct clips (arrows B) from front of VANOS
control unit.
Rotate engine
clocltwise and set camshafts to Top Dead
Center (TDC). Cylinder
1 camshaft lobes will point towards
each other (arrows).
4 Remove plug from below starter and install crankshaft lock-
ing tool
(BMW special tool 11 2 300).

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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
1 VANOS I 4 When engine is started, camshafts are in deactivated
camshaft
retarded Engine I i oil supply
position:
. lntalte camshaft is held in RETARDED position by oil
pressure.
Exhaust camshaft is held in ADVANCED position by
preload spring and oil pressure.
VANOS
Piston out
ECM Piston in Within 2
- 5
seconds (50 engine revolutions), the ECM begins
monitoring and controlling camshaft positions.
The Double VANOS system allows full variability of camshaft
timing up to the limits of the system. When the ECM detects
that the camshafts are in optimum position, the solenoids are
modulated at approximately 100
- 220 Hz to maintain oil pres-
sure on both sides of the actuator pistons to maintain timing.
In models with DME
MS 43.0 (model year2001 and newer),
the engine control module (ECM) detects camshaft position
before the engine starts, thereby adjusting camshaft timing
immediately upon start-up.
NOTE-
. VANOS system troubleshooting and diagnostics is best
accomplished using a scan tool.
. Diagnostic Trouble Codes (DTCs) pertaining to the
VANOS system are listed
in the following table. See also
OED On-Board Diagnostics.
Elevated oil temperatures can cause VANOS to deactivate.
Oil that is too thick (high viscosity) may cause
a DTC to be
set
in the ECM. If VANOS is deactivated (limp-home
mode), there will be a noticeable loss of power.
VANOS fault codes
BMW code P-code Fault description
19
PI529 VANOS solenoid valve activation,
exhaust
21
PI525 VANOS solenoid valve activation,
intake
103
PI519 VANOS faulty reference value
intake
104
PI520 VANOS faulty reference value
exhaust
105
PI522 VANOS stuck (Bank I) intake
106
PI523 VANOS stuck (Bank 2) exhaust

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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.

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... -.
Camshaft Timing chain1
Timing chains, removing
(M52 TU and M54 engines)
Camshaft timing chain removal requires that the oil pan be re-
moved. See
119 Lubrication System. Also required is re-
moval of the VANOS control
unit and disassembly of the
intake and exhaust camshaft sprocket assemblies as de-
scribed earlier in this repair group.
Special BMW
service tools are needed for timing chain re-
moval and installation. The special tools assure proper timing
of the valvetrain. Precise
marlts to set the timing on the cam:
shafts are not provided for reassembly. Read the procedures
through before beginning the job.
CA
UTION-
If the camshafts are not properly timed, the pistons can con-
tact the valves.
- D~sconnect negative (-) cable from battery.
CAUTION-
* Disconnecting the battery may erase fault code@) stored in
control module memory. Check for fault codes using spe-
cial
BMW diagnostic equipment.
Prior to disconnecting the battery, read the battery dis-
connection
cautfons given in 001 General Cautions
and
Warninqs.
- Remove VANOS control unit. See VANOS control unit, re-
moving
(M52 TU and M54 engines).
Remove sealing plug from crankcase below starter and se-
cure crankshaft with
BMW special tool ll 2 300.
Drain engine cooling system. See 170 Radiator and Cool-
ing System.
Remove belt driven cooling fan, fan shroud, and thermostat
housing. See
170 Radiator and Cooling System.
Remove drive belts. See
020 Maintenance.
NOTE-
Mark direction of belt rotation if reusing belt.
- Remove water pump pulley fasteners and pulley.
- Drain engine oil and remove oil pan as described in 119
Lubrication System.

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I Camshaft Timins Chain
4 Using special tool 11 2 450, rotate engine clocltwise to TDC
with number one cylinder cam lobes facing each other (ar-
rows)
as shown.
4 Lock crankshaft in TDC position with BMW special tool 11 3
200 (arrow).
- Remove BMW special tool 11 2 450 and remove hub.
- Remove upper engine oil pan. See 119 Lubrication.
- Remove alternator. See 121 Battery, Starter, Alternator.
- Remove retaining bolt for oil dipstick tube from upper timing
chain cover on right side.
- Remove camshaft position sensor from right upper timing
chain cover.
< Remove right upper timing chain cover:
Remove chain tensioner
(A).
CAUTIOG
Tensioner is under spring tension. Release slowly. 1
Release fasteners (arrows) and remove cover

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Camshaft Timing chain1 - -- -
Using crankshaft center bolt, turn engine clockwise until
number one cylinder (right head) is in
TDC overlap position,
as shown
(arrows).
NOTE-
Number one cylinder is at valve overlap when both the intale
and exhaust valves are starting to open.
< Loosen accessible bolts (arrows) on right exhaust and
intake camshafts (cylinders
1-4) approximately 'I2 turn.
NOTE-
When loosening bolts on camshaft sprocket, counterhold
camshaft using an
27 mm open-end wrench. If necessary.
machine wrench accordingly to prevent damage
to head.
Repeat for accessible bolts of left exhaust and intake
camshafts (cylinders
5-8).
Using crankshaft center bolt, rotate engine one complete ro-
tation to
TDC position. Lobes of camshafts for right cylinder
head (cylinders
1-4) should point to each other (arrows).
- Loosen remaining intake and exhaust camshaft sprocltet
bolts approximately
'I2 turn.

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-
I Lubrication System - I
Oil pressure, checking
The oil pressure warning switch is located at the base of the
oil filter housing.
In 6-cylinder engines access to oil pressure warning switch
connector (arrow) is extremely restricted (intake manifold re.
moved for the purpose of illustration).
V-8 engine oil pressure warning switch (arrow) is at base of
oil filter housing on left engine compartment inner fender.
Oil pressure is tested by removing oil pressure switch and in-
stalling oil pressure gauge in its place.
Unscrew oil filter cap in order to allow engine oil to drain back
down into oil pan.
Disconnect harness connector from oil pressure switch and
remove switch.
NOJE-
Thoroughly clean around the oil pressure switch before
removing it.
Be prepared to catch leaking oil with a shop towel.
- Install pressure gauge in place of oil pressure switch,
- With gauge installed, start engine and allow to reach operat-
ing temperature. Check oil pressure. See Table b.
NOJE-
For the most accurate test results, the engine oil and filter
should be new. The oil should be the correct grade.
Table b. Engine oil pressure
At idle 0.5 bar (7 psi)
At elevated speed
6-cylinder engine 4.0 bar
(59 psi)
V-8 engine 4.5 bar (66 psi)