1999 BMW 525i Workshop Manual

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117-13
Camshaft Timing chain1
< Install seal removing tool (BMW special tool 11 2 380) and
screw in body of puller until it makes firm contact with seal.
Tighten center screw in end of tool to draw out seal.
4 Coat new seal with oil, and use BMW special tool 11 1 220
and crankshaft center bolt to draw seal in flush with timing
case cover.
- Install damper hub and tighten new center bolt finger tight
4 Install angle gauge BMW special tool 11 3 460 as shown.

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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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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
4 Unscrew and remove cylinder head cover studs (arrows) at
rear of cylinder head.
% Secure camshafts in TDC position using BMW special tool
set
11 3 240.
4 Remove access plugs (arrows) from VANOS control unit.

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117-18
Camshaft Timing Chain
4 Loosen 4 bolts (arrows) from exhaust camshait sprocket
(Torx E10).
Press down on secondary chain tensioner and lock into place
using BMW special tool
11 3 292 or a similar size pin.
NOTE-
Two types of secondary timing chain tensioners are used;
one with two holes, and one with a single hole for the
locl pin tool.
Remove VANOS control unit mounting fasteners at front of
cylinder head.
4 Install sprocltet rotating tool (BMW special tool 11 5 490) on
exhaust camshaft.
- Rotate exhaust camshaft sprocket clockwise while sliding
VANOS control unit forward to remove from cylinder head.

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Camshaft Timing chain1
VANOS control unit, installing (M52 engine)
CAUTION-
Incorrect installation of the VANOS control unit may result in
damage to the engine.
- Make sure camshafts and crankshaft are loclted in TDC po-
sition with BMW special tools as described during VANOS
removal.
< Rotate exhaust camshaft sprocket clocltwise (as viewed from
front of engine) using BMW special tool
11 5 490, until detent
position stop is reached.
4 Apply a small amount of liquid gasket sealer (Three Bond
1209
8 or equivalent) to VANOS housing alignment dowels
on front of cylinder head. Install a new
gasket.
< Push VANOS piston gear cup (arrow) into VANOS housing
until it bottoms out. Position VANOS control unit in front of
camshafts, but do not engage splines on gear cup.

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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).