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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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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.
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4 With crankshaft at TDC position, remove vibration damper
bolts (arrows) and remove vibration damper.
< Mount crankshaft holding tool (BMW special tool 11 2 150
and
11 2 410) to crankshaft hub. Counter hold crankshaft and
loosen crankshaft hub retaining bolt.
Crankshaft hub retaining bolt is torqued to
410 Nm (300 ft-lb).
Do not use flywheel
locliing tool to hold cranl(shait stationary
to loosen or tighten crankshaft hub center bolt. Use only the
special tools specified, or equivalent hub holding tool.
- Remove crankshaft hub.
- Remove cylinder cover mounting fasteners and remove cyl-
inder head cover.
NOTE-
The cylinder head cover mounting bolt insulators and gas-
lets should be reinstalled in their original positions. Make
note of their arrangement during removal.
- Drain engine oil, remove oil pan. See 119 Lubrication Sys-
tem.
Remove primary timing chain tensioner (arrow).
CAUTION-
Timing chain tensioner is under spring tension. I
- Remove VANOS control unit. See VANOS control unit, re-
moving
(M52 engine).
- Remove fasteners from intake and exhaust camshaft
sprocket.
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Camshaft Timing chain1
Tap locating dowels into cover until they protrude 2 to 3 mm
from sealing surface.
- Using new gaskets, install lower timing chain cover:
Tap cover into position to engage dowels.
Install timing chain cover fasteners and tighten to
5 Nm (44
in-lb).
Drive dowels in flush to front of cover.
. Tighten cover mounting bolts alternately and in stages.
Install cylinder head to timing chain cover fasteners and
tighten.
Tightening torques Lower timing chain cover to block
M7 15 Nm (1 1 ft-lb)
ME 20 Nm (15 it-lb)
- Replace front crankshaft radial seal. See Crankshaft oil
seal, front, replacing
(M52 engine).
Install engine oil pan using
a new gasket. See 119 Lubrica-
tion System.
Mount primary timing chain sprocket to primary
cha~n so that
arrow on sprocket faces up. Mount sprocket to camshafl so
that tapped holes in camshaft are on left side of elongated
holes in sprocket.
4 Install adjustable timing chain tensioner (BMW special tool
11 4 220). Thread tool in finger tight until slack is removed
from chain.
NOTE-
BMW special tool 11 4 220 is an adjustable timing chain ten-
sioner that simulates the function of the hydraulic tensioner.
- Check that elongated holes in primary sprocket are centered
to bolt holes in camshafl and chain is free of slack.
- Install secondary timing chain guide and secondary chain
tensioner. Tighten mounting bolts (tensioner remains
locited
down).
F81.,,l,ryT-iib.l>nii,:oni-Aii Ri"ilti R
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-- Camshaft Timing Chain -- -
Tightening torque
Vibration damper hub to crankshaft
410 Nm (300 ft-lb)
4 Install cranltshaft hub and vibration damper while aligning
locating hole (arrow) in damper with dowel pin in hub.
Tightening torque
Vibration damper and
pulley to
cranltshaft hub
22 Nm (17 ft-lb)
- Turn engine over by hand in direction of rotation at least two
full rotations. Reinstall camshaft and crankshaft locking
toois
to recheck engine timing. Remove locking tools if no faults
are found.
- Remove BMW special tool 11 3 390 (dummy tensioner) from
side of cyiinder head.
- Install primary chain tensionerso that cutout in tensioner pis-
ton engages chain rail.
Tightening torque
Timing chain tensioner to tensioner sleeve
70 Nm (52 ft-ib)
- Install cylinder head cover mounting studs, camshaft cover,
and cylinder head cover.
Tightening torque Cylinder head cover to cyiinder head
M6 nut 10 Nm (89 in-lb)
MB bolt 22 Nm (17 ft-lb)
- installation of remaining parts is reverse of removal, noting
the following:
When installing thermostat, make sure arrow or vent hole
faces up, if applicable.
Refill cooling system as described in
170 Radiator and
Cooling System.
Fill engine with oil and install new
oil filter as described in
020 Maintenance.
Tightening torque Upper timing chain cover to cylinder head
M6 nut 10 Nm (89 in-lb)
MB bolt 22 Nm (17 ft-lb)
VANOS oil supply pipe to VANOS control
unit banjo bolt
32 Nm (24 ft-ib)
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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
Page 272 of 1002
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1 17-36
Camshaft Timing Chain
1 Double VANOS control unit
1. BoltM6
2. Exhaust camshaft position
sensor
3. Sealing ring
4. Camshaft end sealing plug
-tighten to 50 Nm (37 ft-lb)
5. Camshaft seal cap
6. VANOS hydraulic piston set
screw -CAUTION: left hand
thread -tighten to
10 Nm
(89 in-lb)
7. Nut M7 -tighten to
14 Nm
(1 0 ft-lb)
8. Engine lifting hook
9. Stud M7
10. Nut
M6 -tighten to 10 Nm
(89 lb-in)
11. Gasket
12. Cylinder head
13. Sealing ring
14. Intake camshaft sensol
15. Bolt M6
16. VANOS control unit
17. Copper sealing ring
18. VANOS oil feed line
19. Banjo bolt -tighten to 32 Nm
(24ft-lb)
Page 273 of 1002
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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,