Page 117 of 1002

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Cylinder Head Removal and Installation 1 --
< Remove complete air filter housing assembly with mass air
flow sensor:
Loosen
intalte duct hose clamp (A) at throttle assembly.
Loosen clamp and remove idle control line from intake duct
(B) and disconnect idle speed control valve electrical har-
ness connector.
Disconnect electrical harness connector
(C) from mass air
flow sensor.
Remove air filter housing mounting screw
(D).
Disconnect vent tube (E).
. Loosen air intalte duct clamp (F).
Carefully lifl air filter housing, mass air flow sensor, and in-
take duct hose out of engine bay.
4 Disconnect positive battery cable and remove intake rnani-
fold cover:
Remove protective cover from positive (+)jumper post.
Loosen and remove battery lead mounting nut (A).
Remove lead and push down through intake manifold.
* Remove trim covers (arrows) from fuel injector cover.
Remove cover hold down fasteners and lifl off cover.
4 Worlting above engine, disconnect the following:
Vent line from cylinder head cover. To remove, pinch clips
(arrows).
Electrical harness connector from VANOS solenoid valve
(A).
- Remove oxygen sensors and exhaust manifolds. See 180
Exhaust System.
CAUTION-
Remove oxygen sensors before removing exhaust mani-
fold to prevent damage.
Label oxygen sensor harness connectors so that they
can be reassembled correctly Do not interchange con-
nectors.
NOTE-
Front exhaust manifold must be removed before rear
manifold.
Page 118 of 1002

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. .- -
Cylinder Head Removal and Installation
- Working at side of intake manifold near left strut tower, dis-
connect intake manifold resonance valve electrical harness
connector.
4 Disconnect fuel injector electrical harness connectors from
injectors.
- Use small screwdriver to pry out wire lock clip on fuel injec-
tor
1 connector.
Repeat for remaining injectors.
Release harness conduit fasteners from injector rail.
- Disconnect intake air temperature sensor electrical har-
ness connection (between intake runners for cylinders
3
and 4).
Lift off connector assembly and lay aside.
4 Where applicable, remove schraeder valve cap (arrow) from
fuel
ra~l. Using a tire chuck, blow fuel back through feed line
using a brief burst of compressed air (maximum of
3 bar or
43.5 psi).
WARNING-
Fuel is underpressure (approx. 3 - 5 bar or 45 - 75psi) and
may be expelled. Do not smoke or
work near heaters or
other fire hazards. Keep a fire extinguisher handy Before
d~sconnecting fuel hoses, wrap a cloth around fuel hoses
to absorb any leaking fuel. Catch and
dfspose of escaped
fuel. Plug all open fuel lines.
Always unscrew the fuel tank cap to release pressure
I in the tank before working on the tank or lines.
Disconnect manifold vacuum line (arrow)
Raise car and support in a safe manner,
CAUTION-
Make sure the car is stable and well supported at all times.
Use a professional automotive lift
orjack stands designed for
the purpose. A
floorjack is not adequate support.
Remove protective engine splash guard from below engine.
Page 119 of 1002

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11 3-25
Cylinder Head Removal and Installation
4 Working beneath car (on left side under driver seat), remove
fuel filter cover and clamp
off fuel hose(s).
NOTE-
M54 engines use a single fuel line to the non-return fuel rail.
Disconnect fuel lines by pressing in on spring lock (arrows).
CAUTION--
Fuel may be expelled underpressure. Do not smoke or worlc
near heaters or other fire hazards. Keep a fire extinguisher
handy Before disconnecting fuel hoses, wrap a cloth around
fuel hoses to absorb any leaking fuel. Plug all open fuel lines.
NOJE-
BMW uses various styles of line connections; a one-time
band clamp; a
self-locl(ing connector (that use BMWspecial
tool 16 1 050 to release); and a quick release connector
(above).
4 M52 TU engine: Pull throttle cable out of rubber retainer (A)
and unhook ball end of cable (6) from throttle actuator.
4 Remove fasteners retaining wiring harness at throttle body
and support bracket (arrows).
Page 120 of 1002
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j Cylinder Head Removal and Installation
4 Working at throttle housing, unscrew and disconnect electri-
cal harness plug
(arrow).
4 Disconnect electrical harness connector at fuel tank venting
valve
(A) and vent hose at quick disconnect fitting (arrow).
- Working under intake manifold, disconnect the following:
Engine oil dipstick tube support.
Oil separator return line from dipstick tube.
Knock sensor harness connector from support.
4 Working underneath car, remove intake manifold support
mounting nut
(arrow), located adjacent to left engine mount.
Page 121 of 1002
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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.
Page 124 of 1002

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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.
Page 125 of 1002
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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.
Page 129 of 1002
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11 3-35
- cylinder Head Removal and Installation] -
< Lift off exhaust and intake sprocltets together with secondary
chain, thrust spacer
(A), and splined shafl (B).
CAUTION-
Splined shafts share the same part number for both intake
and exhaust camshafts. Used splined shafts must be
rein-
stalled in their original positions.
Remove exhaust camshaft splined sleeve
(A) and shaft (B).
Remove secondary chain tensloner mounting bolts (arrows)
and remove tensioner with retaining pin in place.