2001 BMW 525i cylinder head bolt

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Cylinder Head and Valvetrain
< Remove oil baffle cover from above intake camshaft(s)
- Rotate engine at crankshaft vibration damper center bolt in
normal direction of rotation (clockwise) until camshaft lobe of
lifter to be tested points away from the lifter, allowing valve to
be completely closed.
Use a plastic or wooden stick to press down on top of lifter
with approximately 3.5 Nm
(2.25 ft-ib) of force.
If the lifter collapses slightly as though spring loaded, air
may be trapped in the lifter.
NOTE-
Air trapped in hydraulic lifters may result from oil foaming (air
being drawn
in by the oil pump). This may be caused by a
faulty oil pump control valve O-ring; leaking oil pump pickup
gaslcet; or by oil starvation to pump.
Press down on top of lifter for
10 to 15 seconds uslng approx-
lmately 6 to 9 Nm (4.5 to 6.75 ft-lb) of force.
If anv clearance is created between the lifter and the
cam-
shafi lobe, the check valve in the lifter is not closing. Re-
place lifter.
- To replace a hydraulic lifter, remove appropriate camshaft.
Refer to camshaft removal procedures given in Camshaft
and lifter removal and installation.
Once camshaft is removed, withdraw faulty
lifter(s) and re-
place with new
lifter(s). Inspect lifter bores for wear and scor-
ing at arrows.
- Reinstall camshafts. See Camshaft and lifter removal and
installation.

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116-12
I Cylinder Head and Valvetrain
Camshaft and lifter removal and installation
(M52 engine)
Camshafts and lifters, removing (M52 engine)
WARNING
-
The process of evenly loosening the camshaft bearing cap
nuts is NOT an acceptable method of removing the cam-
shafts. Special tools should always be used to remove the
camshafts. Be sure to read the procedure
tlirough before
starting a job.
I Allow engine to cool before beginning this procedure. /
- Disconnect negative (-) cable from battery.
CAUTION-
Prior to disconnecting the batfew read the battery discon-
nection cautions given in
001 General Cautions and
Warnings.
- Remove VANOS control unit from cylinder head. See 117
Camshaft Timing Chain.
I I 4 Remove loosened bolts (arrows) from front of exhaust
sprocket
nuts
(arrows) from intake camshaft

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116-14
I Cylinder Head and Valvetrain
4 Remove sensor gear (arrow).
Remove secondary timing chain tensioner retaining bolts
(arrows) and remove tensioner.
Remove timing chain guide
reta~ning bolts (arrows) and
remove guide.

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.
Cylinder Head and Valvetrain
< Remove cylinder head cover retaining studs (arrows) from
center and rear of cylinder head.
< Remove spark plugs and install BMW special tool 11 3 260
(A) and 11 3 270 (6) to cylinder head. Tighten tool retaining
bolts in spark plug bores. Do not overtighten bolts.
Tightening
torque
BMW special tool 11 3 260 I1 1 3 270 to 23 Nm (17 It-lb)
cylinder head
- Remove intake camshaft bearing cap for cylinder number 1.
CA UTIOG
Intake camshaft bearing cap 1 is centered with adapter
sleeves. To avoid
can~sllaft daniage, it must be removed bs-
fore any other caps.
Turn eccentric shaft on special tool until pressure is applied
to camshaft bearing caps.
- Remove remaining bearing cap mounting nuts
- Slowly release pressure on camshaft bearing caps by turning
eccentric shaft. Remove bearing caps and camshaft. Repeat
procedure on remaining camshaft.
CAUTION-
Camshaft bearing caps must be reinstalled in their original lo-
cations.
NOTE-
The camshaft bearing caps are coded with a letter anda
number. For example,
'XI" is the first exhaust camshaft
bearing cap at the front of the engine, and
"El "is the intalce
camshaft bearing cap at the front of the engine.
0 The camshafts are stamped with a code letter - "E" for the
intake side and 'MA" for the exhaust side.
0 "E is for Einlap, (German for intake) and 'XA"is for Auspuff,
(German for exhaust).

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116-18
Cylinder Head and Valvetrain
4 Install camshaft carriers with hydraulic lifters into cylinder
head. Note marks on carriers:
(E) for intake side and (A) for
exhaust side.
4 Center camshaft carrier on pins (arrows) at bearing posi-
tions
2 and 7.
4 Install camshafts with number 1 cylinder camshaft lobes fac-
ing each other (arrows).
CAUTION-
A minimum waiting time is required for the hydraulic lifters to
'bleed down" after installing the camshafts into the cylinder
head, before bringing the pistons to TDC. When the cam-
shafts are removed, the hydraulic
lifers can expand. This ex-
pansion can cause increased valve lift when the camshafts
are bolted down, possibly resulting in piston interference.
Camshaft Installation waiting
times
68" F (20" C) or above 4 minutes
50-68' F (1 0-20°C) 11 minutes
32-50" F (0-1 0" C) 30 minutes

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11 6-22
Cylinder Head and Valvetrain
Remove secondary chain tensioner mounting bolts (arrows)
and remove tensioner with locking tool in place.
Remove primary chain sprocket mounting studs
(arrows) on
exhaust camshaft.
NOTE-
Counterhold camshafts when loosening.
Lifl primary chain sprocket off exhaust camshaft. Remove
sprocket from chain.

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..--.
I Cylinder Head and Valvetrain - I
4 Lift primary chain and hold under tension, rotate engine
against direction of rotation (counterclockwise) approximate-
ly 30".
To prevent damaging valves while
worlcing on camshafts, no
aistons should be in the TDC position.
- Remove BMW special tool set 1 I 3 240 from rear of cylinder
head.
Remove retaining nuts (arrows) and bearing cap
1 of intake
camshaft.
Intake camshaft bearing cap
1 is centered with adapter
sleeves. To avoid camshaft damage, it must be removed be-
fore anv other caos.
4 Fit BMW special tools 11 3 260 (A) and 11 3 270 (B) to cylin-
der head and screw long bolts (aiiows) into spark plug
threads. Tensioners will align with the bearing caps on the in-
take camshaft.
CA UTION--
Do not over torque bolts into spark plug holes. 1
4 Turn eccentric shaft of special tool to pretension intake carn-
shaft bearing caps. Remove nuts on remaining bearing caps.
- Slowly release tension on eccentric shaft and remove BMW
special tools. Remove bearing caps and set aside in order.
Remove camshaft and store safely.
CA U TIOW-
Camshaft bearing caps must be installed in their original lo-
cations.

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-- - . .- -,
Cylinder Head and Valvetrain
4 Rotate camshafts so that intalte and exhaust lobes for cylin-
der
1 face each other (arrows).
CAUJION-
A minimum waiting time is required for the hydraulic lifters to
'bleed down"after installing the camshafts into the cylinder
head, before bringing the piston to TDC. When the camshafts
are removed, the hydraulic lifters can expand. This expan-
sion can cause increased valve lift when the camshafts are
bolted down, possibly resulting in piston interference.
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 cylinder
head over
intalte camshaft and screw long bolts (arrows)
into spark plug threads.
CA UTION-
Do not overtighten bolts into 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 it-ib)
- Release tension on eccentric shaft and remove BMW special
tools
11 3 2601270.
- Repeat procedure for exhaust camshaft.
NOTE-
Observe waiting time for lifter bleed down before continuing
with camshaff installation.
Crankshaft
I valve timing waiting times
68°F (20°C) and higher 5 minutes
50-6S°F(10-20°C) 15 minutes
32-50DF(O-10°C) 30 minutes