2001 BMW 525i cylinder head bolt

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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.

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Cylinder Head Removal and Installation I
Remove cylinder head cover mounting studs (arrows) from
center of cylinder head.
- Remove crankshaft loclting tool from transmission bell hous-
Ing.
Lift primary chain and hold under tension, then rotate engine
at vibration damper in opposite direction of normal rotation
(counterclocltwise) approximately 30".
CAUTION-
By turning crankshait3O0, pistons are movedaway from top
dead center, to prevent possible valve interference to pistons
during camshaft servicing.
- Remove camshaft loclting tools (BMW special tool set 11 3
240) from rear of cylinder head.
4 Remove camshaft bearing cap 1 on intake camshaft.
4 Fit BMW special tools 11 3 260 (A) and 11 3 270 (B) to cyl-
inder head and screw long bolts (arrows) into spark plug
threads. Tensioning pins on tool will align with the bearing
caps on the
intake camshaft.
CAUJION-
Do not over torque bolts into sparkplug holes.

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11 3-38
I Cylinder Head Removal and Installation
< Turn eccentric shaft of special tool to pretension intake cam-
shaft bearing caps. Remove nuts on all intake camshaft bear-
ing caps.
- Slowly release tension on eccentric shaft and remove BMW
spec~al tools. Remove bearing caps and set as~de in order.
Remove camshaft and store safely.
- Repeat procedure for exhaust camshaft.
4 Secure hydraulic lifters in lifter bores using BMW speclal tool
11 3 250, or remove lifters using a magnetic pick-up tool.
With lifters secure or removed, lift out camshaft bearing car-
riers from cylinder head.
Use care to not let hydraulic lifters fall out as camshaft car-
rier is removed.
Hydraulic lifters should be stored
ln an uprightpositlon.
Used hydraulic lifters must be reinstalled into their orig-
inal lifter bores.
4 Remove intake camshaft position sensor (arrow) from side
of cylinder head.
4 Remove secondary chain lowerguide bolts (arrow). Remove
chain guide.

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. - -- -
Cylinder Head Removal and Installation --
Remove bolts (arrows) holding timing chain cover to cylinder
head. (Photo shows camshafts and camshaft bearing caps in
place).
4 Using BMW special tool 11 2 250 or equivalent, loosen cylin-
der head bolts in several stages, in sequence shown. Discard
head bolts.
NOJE-
BMW special tool 11 2 250 is a thin-walled Torx El2 socket
with an extended reach. The cylinder head bolts are re-
cessed into the head below the
camshaft towers with little
working space.
- Lift off cylinder head. Refer to 116 Cylinder Head and Val-
vetrain for cylinder head reconditioning information.
Cylinder head, installing, M52 TU and M54
engines
Clean cylinder head and gasket surfaces of cylinder bloclc
and all timing chain covers.
CAUTION- Remove foreign matter and liquid from bolt holes. Trapped oil
or coolant in bolt holes can cause damage to
blocl~,
CAUJION-
Do not use a metal scraper or wire brush to clean the alumi-
num cylinder head or pistons. 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.
Evaluate cylinder head as shown in
116 Cylinder Head and
Valvetrain.
NOTE- If the cylinder head has been machined, a special 0.3
mm
(0.01 1 in.) thicker gasket should be installed. The thicker
gasket is available from an authorized
BMW dealer and
should be marked accordingly
Cylinder head and valve specifications are covered in 116
Cylinder Head and Valvetrain.

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11 3-40
I Cylinder Head Removal and Installation
Lubricate camshafts, camshaft carriers, bearing caps, hy-
draulic lifters, friction washers, splined shafts and spline hubs
with assembly lubricant before installation.
4 Check that two cylinder head aligning sleeves (arrows) are
correctly positioned in block and are not damaged.
- Apply elastic sealing compound Three Bond 1209 8 to cor-
ner joints on cylinder block to timing chain cover.
- Place new cylinder head gasket on cylinder block.
NOTE-
The word "OBEN" or "TOP printed on the gasket, should
face up. The cylinder headgaslet will fit correctly in only one
orientation.
- Set cylinder head in position, guiding primary chain through
cylinder head opening.
CAUJION-
Make sure the crankshaft, which had been rotated approxi-
mately 30" opposite the direction of engine rotation from
TDC, is still in thatposition before lowering the cylinder head
into position. All pistons must be out of TDC position to pre-
vent
valve/piston interference when the camshafts are in-
stalled.
- Lightly lubricate new cylinder head bolts and washers with
oil. Install bolts and washers finger tight. Install cylinder head
to lower timing chain cover bolts finger tight.
NOJE-
Cylinder head bolts should not be reused. They are
stretch-type bolts and must be replaced whenever loos-
ened.
* Aluminum cylinder blocls use different length cylinder
head bolts and torque values than cast iron blocks.
Check that all washers for
Nle head bolts are in place be-
fore installing the bolts. Some of the washers may be
staked to the cylinder head.
I 12 10 4 2 6 8 141 Tighten cylinder head bolts in correct sequence (1-14)
CA U TIOW-
The bolts should be tightened in three stages as listed below
The final stages require the use of a BMW special tool
11 2
110 or a suitable protractor to tighten the bolts to a specified
torque angle.

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. - ..
Cylinder Head Removal and installation] --
- Secure cylinder head bolts by torquing an additional 90"
each for Stage 2 and 3.
Tightening torques
Cylinder head to engine block
(aluminum block)
Stage
1 40 Nm (30 it-lb)
Stage 2 +90°
Stage 3 80'
4 lnstall intake camshaft position sensor (arrow).
4 Install lower secondary chain guide. Tighten tom bolts to
specifications. The bolt on the intake camshaft side is long
and extends into the engine block.
4 Install and tighten cylinder head-to-lower timing chain cover
bolts (arrows). (Photo shows camshafts in place).
Tightening torque Secondary chain guide to cylinder head
10 Nm (89 in-lb)
Cylinder head to lower timing chain cover
M6 10 Nm (89 in-lb)
M7 15 Nm (1 1 it-lb)

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.-
Cylinder Head Removal and Installation
4 Rotate camshafts until intake and exhaust lobes for cylinder
1 face each other (arrows).
CAUTION-
Be sure that cranlcshaft is stillpositioned at least 30" away
from
TDC.
- Place bearing caps on cams, but do not install retaining nuts.
4 Fit BMW special tool 11 3 260 (A) and 11 3 270 (B) to cylin-
der head over intake camshaft and screw long bolts (arrows)
into spark plug threads.
CAUTIOI\C
Do not overtighten bolts in spark plug holes.
Turn eccentric shaft of special tool to pretension
bearing
caps. Install and torque nuts on intake camshaft bearing
caps.
Tightening torque Camshaft bearing
cap to cylinder head (M7) 14 Nm (10 ft-lb)
Release tension on eccentric
shaft and remove BMW special
tools
11 3 2601270.
Repeat procedure for exhaust camshaft.
CAUTION-
After the camshafts are installed, a minimum waiting time is
required for the hydraulic lifters to 'bleed down" before bring-
ing the crankshaft andpiston back to top
deadcenter. When
the camshafts are removed, the hydraulic lifters can expand.
This expansion can cause increased valve lift when the cam-
shafts are bolted down, possibly resulting in piston interfer-
ence.
Crankshaft
I valve timing waiting times
68.F (20°C) and higher 4 minutes
50-68"F(10-20°C) 11 minutes
32-5O0F(O-10°C) 30 minutes

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-7 Cylinder Head Removal and lnstallat~on -- -- - -
Remove chain and sprockets from tool and slide sprockets
on camshafts. Confirm that gap in intake sprocket splines
lines up with corresponding gap in camshaft splines (arrow).
CAUTIOI\C
Do not alter position of sprockets with respect to chain when
removing
from special tool 11 6 180.
< Align locating tooth of splined shaft with gaps on camshaft
and sprocket. Slide splined shaft onto intake camshaft until
approx.
1 mm (0.04 in) of splines (arrows) are visible.
4 Install intake camshafl spring plate so that FRONT mark is
visible. Install mounting nuts (arrows) finger tight.
Insert sprocket mounting bolts (arrows) on exhaust side
camshaft assembly.
Initially tighten to approx.
5 Nm (44 in-lb) and then back off
by half a turn.