2001 BMW 525i engine wire

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Cylinder Head and valvetrain1
4 Remove camshaft position sensor (A) from timing chain cov-
er. Remove bolts
(arrows) from timing chain covers and re-
move covers from right and left cylinder heads.
4 Counterhold intalte carnshaft on right cylinder head
4 Counterhold right intalte camshaft and remove sprocltet
mounting bolts
(arrows) from right cylinder head.
Remove carnshaft impulse wheel and primary chain
sprocket.
- Slide primary timing chain off sprocltet and suspend chain
with stiff wire to prevent it from dropping into lower timing
chain cover.

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..
ICylinder Head and Valvetrain -.I
4 Counterhold left intake camshaft and remove sprocket
mounting bolts
(arrows) from left cylinder head.
Remove primary chain sprocket.
Slide primary timing chain off sprocket and
supend timing
chain with stiff wire to prevent it from dropping into lower
timing chain cover.
4 Using cranltshaft center bolt, rotate engine counterclockwise
to
45" before TDC position. 45" V.OT mark on pulley will
align with boss cast on engine block
(arrow).
4 Compress secondary chain tensioners and lock (arrows)
using BMW special tool 11 3 310 or a stiff wire.

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1 16-56
Cylinder Head and Valvetrain
This section covers valve removal and reconditioning, includ-
ing valve guides, seats, springs, and valve stem oil seals.
Valves, leak test
To test the valves for leakage, the cylinder head must be dis-
assembled with camshafts and camshaft carriers removed.
With valve assemblies and spark plugs installed, place the
cylinder head on a workbench with the combustion chamber
facing upward. Fill each combustion chamber with a thin non-
flammable liquid. After fifteen minutes,
check the level of the
fluid. If the fluid level in any cylinder drops, that cylinder is not
sealing properly.
Valves, removing and installing
- Remove cylinder head as described in 113 Cylinder Head
Removal and Installation.
CAUTIOI\C
(M52 TU/M54 engines only) Do not let the hydraulic lifters
fall out as the camshaft carrier is removed. Special suction
cups are available from
BMW to hold the hydraulic lifters in
place during carrier removal.
* Hydraulic cam lifters should be stored m an uprfght po-
sition. If necessary, use a magnetic tool to
aidin remov-
al of the lifters.
- Remove valves using a valve spring compressor.
CAUTIOI\C
Label each valve assembly as it is removed so it can be in-
stalled in its original position.
-
- Remove and discard valve stem oil seals from valve guides.
See Valve stem oil seals later in this section.
- Valve installation is reverse of removal. Remove carbon de- - -
posits from the valves using a wire brush or wire wheel. -
-
Valve specifications are listed in Table c. Valve specifica-
tions.

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11 7-52
Camshaft Timing Chain
Remove primary camshaft chain tensioner (arrow) from tim-
ing chain cover.
CAUTIOIG
Primary camshaft chain tensioning piston is under spring
pressure.
Press down on secondary chain tensionerand lock into place
using
BMW special tool 11 3 292 or a similar size wire.
Remove exhaust camshaft impulse wheel
rows). Remove impulse wheel (A).
4 Remove spring plate (A). mounting
nuts
(ar-

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1 17-68
Camshaft Timing Chain
4 Remove left and right side ignition coils and spark plugs:
- Remove positive (+) terminal cable from left cylinder head
cover.
- Unbolt lefl and right side cable ducts from fuel rail,
4 Disconnect fuel injector electrical connectors:
Pry corner of wire lock clip to release connector from injec-
tor
(arrow).
Repeat for all injectors.
Lift off wiring ducts.
4 Remove Fasteners (arrow) from lefl and right cylinder head
cover fasteners and remove covers.

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1 Camshaft Timing Chain
4 Secure right side timing chain and guide rails together with a
plastic wire ties
(arrow).
4 Remove lower timing chain cover bolts (arrows) and cover.
- Remove wire ties supporting guide rails.
-
Q Remove sprocket from intake camshafts and remove timing
chain.
If necessary, remove tensioning rail
(A), reversing rail (B),
and guide rail (C) to remove timing chain.

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Camshaft Timing Chain1
lnstall timing chain and intake sprocket to intake camshaft on
right cylinder head. While pressing in on chain tensioner rail,
confirm camshaft flange bores (arrows) are centered in
sprocket mounting slots.
NOTE-
Pressing in on rail will remove slack and reposition sprockets.
If
necessarx remove sproclets and align bores centrally.
lnstall intake camshaft sensor gear with notch upward (ar-
row) at right cylinder head.
- Finger tighten mounting screws.
- lnstall remaining sprocket bolts to intake camshaft finger tight
at left cylinder head.
- Press timing chain tensioning rail against timing chain. lnstall
plastic wire
tie, to hold rail against chain.
- lnstall lower timing chain cover:
Clean sealing surfaces and check sleeves are properly
seated.
Apply a thin coat of Three Bond 1209
8 to front and back
of new seal. Also coat joints where block meets cylinder
heads and oil pan.
Initially hand tighten bolts in alternate sequence to firmly
seat cover.
Tighten fasteners to final specification in alternate
sequence.
Tightening torques Lower timing cover
M6 bolts 10 Nrn (89 in-lb)
M7 bolts 15 Nm (1 1 ft-lb)
ME bolts 22 Nm (1 6 ft-lb)
M10 bolts 47 Nm (35 ft-lb)
- Replace radial seal in lower timing chain cover, then reinstall
crankshaft hub, center bolt, and vibration damper. See
Crankshaft oil seal, replacing
(M62 and M62 TU engines).
- lnstall oil pan with new gasket. See 119 Lubrication Sys-
tem.
- Lock crankshaft in place with BMW special tool 11 2 300

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[camshaft Timina Chain
< Remove cylinder head cover sealing gaskets from lefl cylin-
der head cover. Install
BMW special tool 11 1 412 into gasket
groove of cylinder head cover.
Install lefl cylinder head cover. Fit cylinder head cover re-
taining nuts to cylinder head cover studs at cylinders
5 and
6 (first two cylinders on left side cylinder bank).
Tighten nuts uniformly in
'I2 turn steps
Tightening torque
Timing case cover to head
15 Nm (1 1 ft-lb)
- Remove special tool 11 1 41 2 and install new gaskets to cyl-
inder head cover:
Clean gasket groove and install new gasket.
Apply Three Bond
12098sealant tojoint between cylinder
head and timing cover and at half-moon shaped cut-outs.
Tighten cylinder head cover nuts.
Tightening torque Cylinder head cover to head
I5 Nm (1 1 ft-lb)
- Remainder of installation is reverse of removal, noting the fol-
lowing:
Where applicable remove protective film from gaskets.
Use new gaskets when mounting intake manifold. Tighten
nuts finger tight first, then torque to specification in stages
worlting diagonally from center out.
Ground straps for ignition coil harnesses are at cylinders
no.
3 and no. 7. See 120 Ignition System.
Refill and bleed cooling system as described in
170 Radi-
ator and Cooling System.
Change engine oil and filter as described in
020 Mainte-
nance.
CAUTIOI\C
To prevent damaging engine electrical systems, be sure to in-
stall ail ground wires previously removed.