2001 BMW 525i cylinder head bolt

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Engine Removal and lnstallationl
< Remove positive battery cable and intake manifold cover:
Remove protective cover from positive (+)jump start post
(4.
Loosen and remove battery lead mounting nut.
Remove lead and push down through intake manifold
Remove trim covers
(arrows) from fuel injector cover.
Remove cover hold down bolts and lift off cover.
Working above engine, disconnect the following:
Vent line from cylinder head cover (A).
M52 engine: Oxygen sensor connectors (8).
Electrical harness connector from intalte camshaft VANOS
solenoid valve
(C).
M52 engine: Disconnect electrical harness connectors at
throttle valve position switch
(D), ASC valve position switch
(E), fuel injector harness (F) and vent valve (G).
CAUTION-
Be sure to mark oxygen sensor harness connectors so that
they can be reassembled correctly Do not interchange con-
nectors.
4 M52 TU, M54 engine: Disconnect fuel injector electrical con-
nectors from injectors.
Use small screwdriverto pry one corner of wire lock clip on
fuel injector
1 connector.
Repeat for all injectors.
Lifl off connector loom and lay aside.

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11 3-2
Cylinder Head Removal and Installation
This group covers cylinder head removal and installation as
well as cylinder
headlvalve diagnostic procedures.
In the procedures in this repair group, engines are referred to
by engine code. If necessary, see
100 Engine-General for
engine code and application information.
The information given in this repair group assumes that the
engine is installed in the engine bay. On the
6-cylinder en-
gines, the VANOS control unit must be removed in orderto re-
move the cylinder head from the engine block. On
M52TU
and M54 engines, camshafts must be removed from the cylin-
der head before the head is removed.
The cylinder head removal and installation procedures for the
M62 V-8 are also included, butthe proceduresforthe M62TU
V-8 with VANOS are not provided.
For cylinder head and valvetrain reconditioning information,
see
116 Cylinder Head and Valvetrain.
For specific repair procedures, refer to the appropriate repair
group:
020 Maintenance
116 Cylinder Head and Valvetrain
117 Camshaft Timing Chain
170 Radiator and Cooling System
610 Component locations
NOTE-
If a head gasket problem is suspected, a compression test or
leak-down test will usually detect the fault See Diagnostic
Testing later
in this group.
Special tools
Special BMW service tools are required to properly remove
and install the cylinder head on engines covered by this man-
ual. The special tools are used to time the valvetrain to the
crankshaft, and to remove the VANOS control unit, the cam-
shafts and the
Tom (El2) head bolts. Read the entire proce-
dure through before beginning the job.

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11 3-3
Cylinder Head Removal and Installation
4 Rotary angle torque dial gauge
(Tool No. BMW
11 2 250100 9 120)
4 El2 Torx socket for cylinder head bolts
(Tool No.
BMW 11 2 250)
4 Crankshaft loclting tool
(Tool No.
BMW 11 2 300)
4 Camshaft locking tool set, 6-cylinder
/I (Tool No, BMW 11 3 240)
< Timing chain adjustable tension setup tool, 6-cylinder
(Tool No.
BMW 11 4 220)
>
Double VANOS adiustment date
4 Secondary sprocket setup tool for double VANOS
(Tool No. BMW
11 6 180)

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-
Cylinder Head Removal and Installation c
q Remove secondary air inject~on check valve (arrow).
4 Remove cylinder head top cover:
Remove plastic trim caps (arrows).
Remove engine oil filler cap.
Remove cover hold down fasteners and lift off cover.
4 Remove ignition coils:
Disconnect ignition coil harness connectors.
. Remove coil mounting fasteners.
Remove coils.
Remove ground straps.
NOTE-
Make note of ground wire at mounting studs arrangement
during removal.
- Remove sparlc plugs.
- Remove cylinder head cover mounting fasteners and remove
cylinder head cover.
NOTE-
The cylinder head cover mounting bolt insulators and gas-
lets should be reinstalled in their original locations. Make
note of their arrangement during removal.

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- - , -. I Cylinder Head Removal and lnstallatio~
4 Remove oil baffle cover from above intake camshaft.
4 Unscrew and remove three cylinder head cover studs (ar-
rows)
at rear of cylinder head.
Set engine to approximate top dead center
(TDC) by turning
crankshaft bolt in direction of rotation (clocltwise when
viewed from front of engine) until camshaft lobes for cylinder
1 face each other (dotted lines) and arrows on camshaft
sprocltets face up.
- Set engine to TDC by aligning "OIP mark of vibration damp-
er with boss cast on lower timing chain cover.
< Lock cranltshaft at TDC:
Remove sealing plug from bore on lower left side of engine
block below starter. Secure crankshaft in
TDC position with
BMW special tool 11 2 300.

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11 3-1 4
Cylinder Head Removal and Installation
4 Secure camshafts in TDC position using BMW special tool
set
11 3 240.
4 Remove access plugs from VANOS control unit in front of
exhaust camshaft sprocket.
Remove
4 bolts (arrows) from exhaust camshaft sprocket
(Torx E10).
CAUTION-
Hold the camshaft stationary (at hex on camshaft) when loos-
eninq or tiqhteninq sprocl(et mounting fasteners. r
Press down on secondary chain tensioner and lock into place
using
BMW special tool 11 3 292 or a similar size pin.
NOTE-
Some tensioners may have a single hole for special tool.
Remove secondary chain tensioner.
Disconnect harness connector and oil line fitting from bottom
of VANOS control unit.
NOTE-
Wrap the VANOS oil line fitting with a shop rag to absorb
leaking oil.
Remove VANOS control unit mounting nuts and bolt at front
of cylinder head.

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113-16
Cylinder Head Removal and Installation
- Remove secondary timing chain and sprockets:
Remove mounting nuts from front of intake camshaft
sprocket. Remove and label shim.
CAUTION-
Hold the camshaft stationary (at hex on camshaft) when loos-
ening or tightening sprocket mounting fasteners.
Remove mounting nuts from front of exhaust camshaft
sprocket and remove and label thrust washer.
NOTE-
Where applicable, make note of thrust washerpositions. The
thicker
(0.4 mm) washer is mounted outermost.
- Remove secondary sprockets together with camshaft tim-
ing chain from front of camshafts.
CAUTION-
The camshafts must be locledin the TDCposition using the
special service tool as described earlier: The arrows on the
sprockets should not be used to accurately set the engine to
TDC. The tool holds the camshafts parallel to each other and
NOTE-
Do not remove the sprocl parts are being replaced. Wire tie each sprocket to the chain
to
Iceep the sproclefs timed to each other:
CAUTIOI\C
The crankshaft must not be allowed to rotate once the cam-
shaft timing chain is removed. The pistons can
contact the
valves.
Unscrew timing chain guide and remove.
Lift off primary sprocket with chain.
Secure chain with wire to prevent chain from dropping into
lower timing cover.
Unscrew timing case cover to cylinder head bolts (arrows).
NOTE-
Photo shows timing chain guide in place; it should first be re-
moved as described previously.
Remove crankshaft locking tool
(BMW special tool 11 2 300).
Using the crankshaft vibration damper bolt, turn engine op-
posite of normal direction of rotation (counterclocltwise as
viewed from the front) approximately 30". This prevents ac-
cidental contact between valves and pistons during installa-
tion.

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Cylinder Head Removal -- and lnstallati~i
4 Cylinder head bolt loosening sequence.
- Using BMW special tool 11 2 250 or an equivalent tool, loos-
en cylinder head bolts in sequence. Discard head bolts.
- Separate the cylinder head from the block and remove head.
Evaluate head as described in
116 Cylinder Head and Val-
vetrain.
Cylinder head, installing, M52 engine
If the camshafts were removed and installed while the cylin-
der head was off, a minimum waiting time is required after in-
stalling the camshafts. When the camshafts are removed, the
hydraulic lifters can expand. This expansion can cause in-
creased valve lift when the camshafts are bolted down, result-
ing in open valves.
Camshaft installation waiting times
68" F (20" C) and higher 4 minutes
50.68' F (1 0-20" C) 11 minutes
32-50' F (0-1 0" C) 30 minutes
- Clean cylinder head and gasket surfaces of cylinder block
and all timing chain covers.
CAUTION-
Do not use a metal scraper or wire brush to clean the alumi-
num cylinder head orpistons. If necessary, use a hard wood-
en orplastic scraper. Also available are abrasive discs to be
used in conjunction with an electric drill. Be sure to use the
correct disc for the type of metal being cleaned.
- Remove all debris and fluids from bolt holes and clean with a
thread chaser.
- Check gasket surface of cylinder head and cylinder block for
warpage using a straight edge.
NOTE-
If the cylinder head has been machined, a special 0.3 mm
thicker gasket should be installed. The thicker
gasket is avail-
able from an authorized
BMW dealer.