1997 BMW 540i ECU

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I Cylinder Head Removal and Installation
4 Drain engine coolant and remove coolant hoses:
Remove expansion tank cap on radiator.
Place a
3 gallon pail beneath engine to capture coolant
Remove coolant drain plug (arrow) located on exhaust
side of cylinder
2 of engine block.
4 Drain radiator into a 3 gallon pail by removing plastic drain
plug (arrow) completely.
Use caution when draining and disposing of engine coolant.
Coolant is poisonous andlethal to humans andpets. Pets are
attracted to coolant because of its sweet smell and taste.
Seek medical
attention immediately if coolant is ingested.
NOTE-
Catch and dispose of drained coolant according to local,
state, and federal laws.
4 Remove thermostat housing:
. Disconnect electrical harness connector at thermostat
housing.
. Remove hoses from thermostat hous~ng by releasing loclts
(arrows).
Unbolt
(4 bolts) and remove thermostat hous~ng.
- On vehicles equipped with mechanical cooling fan: Remove
belt-driven cooling fan and radiator shroud as described in
170 Radiator and Cooling System.
CAUTIOI\C
32 mm radiator fan mounting nut has left hand threads. r
4 Remove fasteners (arrows) from heater bypass tube. Pull
tube out of cylinder head and set to side, leaving heater hose
connected.
- Unbolt power steering fluid reservoir and pull aside without
disconnecting hoses. Secure to fender with cord or stiff wire.

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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.

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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] --
- 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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11 3-44
I Cylinder Head Removal and Installation
4 Secure camshafts in TDC position using BMW special tool
set
11 3 240.
4 In necessary, turn camshaft slightly so that special tools are
squarely seated on cylinder head.
4 Lift timing chain and hold under tension.

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. .- --
Cylinder Head Removal and Installation
Secure camshaft sprockets and impulse wheels:
Tighten mounting screws
(A) on exhaust camshaft impulse
wheel to approx.
5 Nm (44 in-lb).
Tighten mounting nuts
(8) on exhaust and intake sprocket
assemblies to approx.
5 Nm (44 in-lb).
Torque down mounting screws (A) and nuts (B) to final
specifications.
Tightening torques
sprocket assembly to camshaft
initial torque
5 Nm (44 in-lb)
Sprocket assembly
wheel to camshaft
M7 torx screws (A) 20 Nm (15 ft-lb)
M6 mounting nuts (5) 10 Nm (8 ft-lb)
- Remove crankshaft locking tool from transmission bell hous-
ing so that crankshaft is no longer secured in
TDC position.
- Remove camshaft locking tools from cylinder head.
4 Turn engine over twice in direction of rotation until cylinder 1
intake and exhaust camshaft lobes (arrows) face each other.
- Secure crankshaft in TDC position with BMW special tool 11
2 300.
4 Place BMW special tool set 11 3 240 over camshafts and
measure clearances.
CAUTION-
- If the exhaust side of the tool (A) is not flush with tlie head,
camshaft timing is incorrect Reset camshaft timing as de-
scribed in
117 Camshaft Timing Chain.
* Due to flexible sprocket design, VANOS unit tolerances
and play in the VANOS splines, when the camshaft tim-
ing is set correctly, the intake side of special tool
11 3
240 (6) may be up to 1 mm (0.04 in.) above the surface
of the cylinder head. This is normal. Reassemble en-
gine.
Othe~lise, reset camshaft timing as described in
11 7 Camshaft Timing Chain.
- Remove BMW special tool 11 6 150 from front of cylinder
head.

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. ." ".
[Cylinder Head Removal and Installation - .. - -1 -
4 Insert and secure VANOS sealing plugs (arrows) with new
sealing O-rings.
Tightening torque Sealing
plug to VANOS 50
Nm (37 ft-lb)
4 Install coolant pipe fasteners at base of cylinder head and
tighten fasteners (arrows).
NOTE-
Use new sealing O-ring on coolant pipe.
- lnstall VANOS oil line banjo bolt with new seals. Attach oil
line to VANOS unit.
Tightening torque Oil line to VANOS unit
(banjo bolt) 32
Nm (24 ft-ib)
- Remove adjustable timing chain tensioner tool and reinstall
chain tensioner.
Tightening torque Primary chain tensioner cylinder to
cylinder head 70
Nm
(52 fi-ib)
- Remove flywheel locking tool from transmission bell housing.
Replace special tool bore sealing plug.
- Remove camshaft locking tools from cylinder head
4 lnstall intake camshaft cover and cylinder head cover.
0 Check for correct seating of half-moon seals (A) in back of
cylinder head cover.
Use a small amount of Three Bond
1209 8 or equivalent
sealant at corners
(B) of half-moon cutouts.
Seat gasket and seal corners in front of cylinder head at
VANOS unit.
Tightening torque
Cylinder head cover to cylinder head
(M6) 10 Nm (89 in-lb)

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1 13-65
Cylinder Head Removal and Installation /
Loosen chain rail set screw (arrow) 3 full
move).
NOTE-
Allen screw secures crankcase vent tube
4 Loosen and turns
(do not re-
in cylinder head.
remove chain guide rail fasteners (arrow).
Slide oil separator
(A) out of cranltcase vent connecting
bracket (arrows).
CAUTIOI\C
When removing the cylinder head carefully press oil separa-
tor outwards.
Loosen cylinder head bolts in sequence
1-10 as shown (ar-
rows) and discard used head bolts.
Lift cylinder head off engine block while pressing out on oil
separator.
CAUTIOI\C
Be careful not to damage oil separator while removing cylin-
der head.