2001 BMW 525i camshaft

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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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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 Chain
< While pressing down on secondary timing chain tensioner
install locking tool (BMW
11 3 292) or a similar pin.
NOTE-
Two types of secondary timing chain tensioners are used,
with either two holes (shown) or a single hole for the
locking
pin tool.
- Remove intake and exhaust sprockets together with
secondary chain.
< Remove secondary timing chain tensioner bolts (arrows)
and remove tensioner.
- Remove primary timing chain sprocket from exhaust
camshaft.
- Remove sprocket and hang timing chain from end of exhaust
camshaft.
4 Remove secondary chain guide bolts (arrows) and remove
guide.

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Camshaft Timing chain1
Using a drift, drive two locating dowels (arrows) in lower
timing cover toward rear of car.
4 Remove timing cover mounting bolts (arrows).
* Carefully slide cover with water pump forward to remove
CAUTION-
Use care when removing the cover from the cylinder head
gasket If the cover is stuck, use a sharp knife to separate
it from the head gasket.
If cylinder head gasket is damaged, remove cylinder
head and replace head
gaslet. See 113 Cylinder
head and valvetrain.
- Remove timing cover locating dowels by driving them
forward.
- Lift primary chain sprocket off crankshaft sprocket and
remove chain.

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1 17-30
I Camshaft Timing Chain
Timing chain, installing
(M52 engine)
CAUTION-
The procedure outlined below assumes that the camshafts
and the crankshaft are
lockedin the TDCposition with BMW
special tools.
- Inspect timing chain and sprocltets and guide rails for wear.
Replace worn parts.
NOTE-
If any of the sprockets are being replaced due to wear, the
chain should also be replaced.
Install primary timing chain
on exhaust camshaft. to crankshait
sprocket and hang
4 Apply a small bead oi silicon sealer (Three Bond 1209 @or
equivalent) to corners where tim~ng cover meets cylinder
head
(arrows).

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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).
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