1999 BMW 525i Workshop Manual

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11 3-27
Cylinder Head Removal and Installation
< Remove fuel rail mounting bolts (arrows):
- Carefully pry fuel rail off manifold.
Separate fuel line support bracket at rear of intake mani-
fold.
Guide fuel
line(s) out of rear of engine compartment while
lifting fuel rail out.
4 Remove intake manifold mountino hardware (arrows).
I from falling into the engine intake. I
4 Remove cylinder head top cover:
- Remove plastic trim caps (arrows).
Remove cover hold down fasteners and
lilt off cover.

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I Cylinder Head Removal and Installation
4 Drain engine coolant and remove coolant hoses:
Remove expansion tank cap on radiator.
Place a
3 gallon pail beneath engine to capture coolant
Remove coolant drain plug (arrow) located on exhaust
side of cylinder
2 of engine block.
4 Drain radiator into a 3 gallon pail by removing plastic drain
plug (arrow) completely.
Use caution when draining and disposing of engine coolant.
Coolant is poisonous andlethal to humans andpets. Pets are
attracted to coolant because of its sweet smell and taste.
Seek medical
attention immediately if coolant is ingested.
NOTE-
Catch and dispose of drained coolant according to local,
state, and federal laws.
4 Remove thermostat housing:
. Disconnect electrical harness connector at thermostat
housing.
. Remove hoses from thermostat hous~ng by releasing loclts
(arrows).
Unbolt
(4 bolts) and remove thermostat hous~ng.
- On vehicles equipped with mechanical cooling fan: Remove
belt-driven cooling fan and radiator shroud as described in
170 Radiator and Cooling System.
CAUTIOI\C
32 mm radiator fan mounting nut has left hand threads. r
4 Remove fasteners (arrows) from heater bypass tube. Pull
tube out of cylinder head and set to side, leaving heater hose
connected.
- Unbolt power steering fluid reservoir and pull aside without
disconnecting hoses. Secure to fender with cord or stiff wire.

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Cylinder Head Removal and Installation
4 If applicable, remove secondary air injection pump:
Disconnect hose at one-way valve
(A).
Remove bolts at support bracket on strut tower (arrows).
Disconnect electrical harness from bottom of secondary
air injection pump.
Remove mounting bracket from strut tower.
4 Remove ignition coils:
* Disconnect ignition coil harness connectors.
Remove coil mounting fasteners.
Remove coils.
* Remove ground straps.
CA UTIOI\C
Note location of all ground wires. Failure to reinstall grounds
can result in permanent damage to engine control module or
ignition system components.
Set coil harness to side of engine compartment
- Remove cylinder head cover mounting fasteners and remove
cylinder head cover.
NOTE-
The cylinder head cover mounting bolt insulators and gas-
ltets should be reinstalled in their original locations. Male
note of their arrangement during removal.
- Remove spark plugs
4 Remove oil baffle cover from above intake camshaft.

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Cylinder Head Removal and installation - - .- - - - -
4 Disconnect electrical harness connections at exhaust cam-
shaft position sensor and exhaust camshaft VANOS control
valve (arrows).
4 Remove banjo bolt from VANOS unit oil pressure line. Use
banjo bolt to attach
BMW special tool 11 3 450 (compressed
air fitting) to VANOS control unit.
CAUTIOI\C
Oil will drain from pressure line. Have a drain container and
rags ready Do not allow oil to run onto drive belts.
4 Cover oil hole (arrow) in VANOS unit with shop towel to cap-
ture oil which will spray when compressed air is applied.
- Connect compressed air line to air fitting. Apply air pressure
set to
2-8 bar (30-1 15 psi).
4 With compressed air line connected, rotate engine at vibra-
tion damper in direction of rotation (clockwise) at least twice,
until cylinder 1 intake and exhaust camshaft lobes face each
other (arrows) in the top dead center (TDC) position for cyl-
inder
1.
CAUTION--
Do not rotate engine counterclocltwise to reach the top dead
center position. If engine rotated beyond top dead center;
complete another two complete rotations.

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11 3-31
Cylinder Head Removal and Installation
Remove sealing plug from special tool bore on lower left side
of engine block near flywheel. Secure crankshaft in TDC po-
sition with
BMW special tool l l 2 300 (arrow).
4 Unscrew and remove two cylinder head cover studs
(arrows) at rear of cylinder head.
4 Secure camshafts in TDC position using BMW special tool
set
11 3 240.
- Disconnect compressed air line, leaving compressed air fit
ting attached to VANOS unit.
4 Unscrew sealing plugs (arrows) from VANOS unit.

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[Cylinderead Removal -. . and Installation -7 - . ..
4 Oil will drain from plugs (arrows) when removed. Have a
container and rags ready. Do not allow oil to run onto drive
belts.
Pull sealing caps straight out of VANOS unit using short nee-
dle nose pliers.
NOTE-
Additional oil may drain from VANOS unit.
Remove set screws (left-hand thread) on ends of intake and
exhaust camshafts.
CAUTION-
Set screws have left-hand threads. Loosen in clocltwise di-
rection.

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- -
-- .- Cylinder ~ead~ernoval and Installation I - -.
Remove VANOS unit:
Remove engine lifting eye.
- Remove VANOS mounting nuts (arrows) and pull VANOS
unit and metal gasket off.
CAUTION-
Do not crank the engine with VANOS unit removed. Pis-
tonhalve inteiference may result.
NOTE-
The VANOS unit will contain a small quantity of oil. Place
shop towel to catch oil as unit is removed or tilted.
CAUTION-
If the VANOS adjustment unit is replaced, or if operations are
completed that may change the timing of
the camshafts, the
camshaft timing must be checked. See
11 7Camshaft Timing
Chain.
4 Remove primary camshaft chain tensioner cylinder (arrow).
CAUTION-
Primary camshaft chain tensioner is under spring pressure.
Press down on secondary chain tensionerand lock into place
using
BMW special tool 11 3 291, or a thin drifl or pin.

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- -
I Cylinder Head emo oval and Installation -
< Remove exhaust camshaft impulse wheel mounting nuts
(arrows). Remove impulse wheel
(A).
4 Remove spring plate (A).
4 Remove intake camshaft sprocltet mounting nuts (arrows)
and remove spring plate (labelled
FRONT).
< Remove torx screws from exhaust camshaft sprocket
(arrows).