1998 BMW 540i Spark plug torque

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Maintenance
continue to operate as designed. Extending the replacement
interval may void the emission control warranty coverage.
See
180 Exhaust System for information on replacing the
oxygen sensors.
Tightening torque
Oxvoen sensor to exhaust
manifold 50 Nrn (37 ft-lb)
NOTE-
A special soclet for replacing the oxygen sensor is available
from most automotive parts stores. The soclet has
a groove
cut down one side to allow the sensor to be installed without
damaging the wire harness.
Power steering fluid, checking level
The power steering system is permanently filled and does not
have a drain. Routinely adding ATF is not required unless the
system is leaking.
4 To check power steering fluid level in fluid reservoir:
Park car on level ground with engine off.
Level is correct
if it is between MlN and MAX marks on
dipstick.
If level is below
MlN mark, add fluid to reservoir to bring
level up.
* Hand-tighten reservoir cap.
Power steering fluid
Dexron
1iiO ATF or equivalent
Spark plugs
E39 models through model year 1998 were equipped with
spark plugs with two electrodes. These are gapped to
0.7 mm
(0.028 in) by the manufacturer and are not adjustable.
Starting with 1999 models, long life spark plugs with
3 or four
electrodes were used. These can be retroactively fitted to
earlier
models. The recommended spark plug replacement
interval
forthese is 100,000 miles.The electrode gap in these
spark plugs is not adjustable.
Spark plug applications
M52 Bosch FBLDCR
M52 TU, M54 Bosch FGR7DQP or NGK BKRBEQUP
M62 to 7/97 Bosch F7LDCR or NGK BKR6EK
M62 from 7/97 Bosch F9LDCR
M62 TU Bosch FGR7DQP or NGK BKRGEQUP

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020-22 Maintenance
1
- Installation is reverse of removal, bearing in mind the
following:
Lightly lubricate new
spark plug threads with
copper-based anti-seize compound.
Thread plugs into cylinder head by hand to prevent
cross-threading.
. Be sure to reinstall and tighten coil grounds.
Tightening torque Spark plug
to cylinder head 25 Nm (18 It-lb)
Interior ventilation microfilter, replacing
Two interior ventilation microfilters are used, one on each
side of the engine compartment at the fire wall.
< To replace the microfilter, unclip the wire fastener and
remove the cover.
Lift out the filter, and replace. Left side shown; right is
similar.
Replace cover and clip wire fastener to retain cover.
Battery, checking, cleaning, and replacing
The battery Is located in the right side of the luggage compart-
ment. Simple maintenance of the battery and its terminal
connections will ensure maximum starting periormance,
especially in winter when colder temperatures reduce battery
power.
Battery cables should be tight. The terminals, cable clamps
and battery case should be free of the white deposits that
indicate corrosion and acid salts. Even a thin layer of dust
containing conductive acid salts can cause battery discharge.

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. .- . --
Lr -- - - - -- Cylinder Head Removal and Installation I -
- Release pressure at compression gauge valve, then remove
gauge from spark plug hole. Repeat test for each cylinder
and compare results with values given in Table a.
Table a. Compression testing specifications
Minimum compression
6-cylinder
10-1 1 bar (142-156 psi)
V-8 12-14 bar (174-203 psi)
Maximum difference between
cylinders (all engines)
0.5 bar (7 psi)
- Compression readings may be interpreted as follows:
Low compression indicates a poorly sealed combustion
chamber.
0 Relatively even pressures that are below specification nor-
mally indicate worn piston rings
andlor cylinder walls.
Erratic values tend to indicate valve leakage.
Dramatic differences between cylinders are often a sign of
a failed head
gasket, burned valve, or broken piston ring.
- If readings are within specifications, reinstall spark plugs and
ignition coils.
NOTE-
Used spark plugs should be reinstalled in the same cylinder
from which they were removed.
Tightening torque Spark plug to cylinder head 25 Nm
(18 ft-lb)
lanition coils to cylinder head 10 Nm (7.5 ft-lb)
- Remainder of installation is reverse of removal. Be sure to re-
install all wires disconnected during test, especially ground
wires at coils and cylinder head cover (where applicable).
Wet compression test
To further help analyze the source of poorcompression,awet
compression test is the next step.
- Repeat compression test, this time squirt a teaspoon of oil
into each cylinder. The oil will temporarily help seal between
piston rings and cylinder wall, practically eliminating leakage
past rings for a short time.
- If this test yields a higher reading than "dry" compression
test, there is probably leakage between piston rings and
cylinder walls, due either to wear or to broken piston rings.
- Little or no change in compression reading indicates other
leakage, probably from valves.

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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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.-
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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11 3-56
I Cvlinder Head Removal and Installation
- Installation of the remaining parts is reverse or removal, not-
ing the following:
- Refill cooling system as described in 170 Radiator and
Cooling System.
Change engine oil and filter as described in
020 Mainte-
nance.
If necessary, adjust accelerator cable.
a Reconnect battery.
CAUTION- To prevent damaging the engine electronic systems, installall
ground wire previously removed, including the ground wires
for the
ionition coils.
Tightening torque Coolant drain
pluq to cylinder bloclc 25 Nm (1 8 ft-lb)
Radiator cooling fan to coolant pump 40 Nm (30 ft-lb) -
Radiator drain screw to radiator 2.5
Nm (22 in-lb)
spark plug to cylinder head 25
Nm (1 8 ft-lb)
CYLINDER MEAD REMOVAL AND
INSTALLATION (M62 ENGINE)
This procedure covers cylinder head removal and installation
for the
M62 V-8 engine. Procedures forthe M62 TU VANOS
engine are not covered in this manual.
Intake manifold, left cylinder head, and right cylinder head re-
moval and installation are written as separate procedures.
The intake manifold must be removed before the cylinder
heads can be removed.
WARNING
-
Due to risk of personal injuv be sure the engine is cold be-
fore beginning the removal procedure.
Cylinder head removal and installation requires multiple spe-
cial service tools. Read the entire procedure before beginning
the repair.
Intake manifold, removal and installation,
M62 engine
- Disconnect negative (-) battery cable.
CAUTION- Prior to disconnecting the
batterj read the baitery discon-
nection cautions
in 001 General Cautions and Warnings.

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/Cylinder Head Removal and Installation
- Remainder of installation is reverse of removal, noting the fol-
lowing:
Use new gaskets when mounting intake
manifold. Tighten
nuts finger tight first, then torque to specification in stages
working diagonally from center out.
Be sure to reinstall ignition coil ground straps at cylinders
no.
3 and no. 7. See 120 Ignition System.
Reinstall cooling fan and shroud. See
170 Radiator and
Cooling 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.
CA UTIOG
To prevent damaging engine electricalsystems, be sure to in-
stall all ground wires previously removed.
Tightening torques
Camshaft sprocket to camshaft 15
Nm (11 H-lb)
Coolant manifold to cylinder head 10 Nm (7.5 H-lb)
Cylinder head cover nuts 10 Nm (7.5 ft-lb)
Exhaust manifold to head 22 Nm (17 ft-lb)
Engine mounts to subirame 42 Nm (30 ft-lb)
Spark plugs to cylinder head 22 Nm (17 ft-lb)
Right cylinder head, removing, M62 engine
- Remove left side exhaust manifold. See 180 Exhaust Sys-
tem.
- Remove intake manifold. See Intake manifold, removal
and installation,
M62 engine.
- Drain engine coolant. See 170 Radiator and Cooling Sys-
tem.
WARNING-
Use extreme caution when draining and disposing of engine
coolant.
Coolanl is poisonous andlellial lo liumans andpels.
Pets are
altracled to coolant because of 11s sfieet smell and
fasle. Seelc medcal anenfion immed~alely if coolant is ingesl-
. .-
< Remove engine coolant manlold mo~nlng fasreners and
carei~lly remove manifo d.
. I
NOTE
Engine 8s slioivn removed lor clarify

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1 13-82
1 Cylinder Head Removal and Installation
4 Reinstall cylinder head covers to right and left cylinder heads
using new gaskets.
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
sealer at corners
(B) of half-moon cutouts.
- Install cylinder head cover fasteners and tighten uniformly in
'I2 turn steps.
Tightening torque Cvlinder head cover fasteners
10 Nm (7.5 It-lb)
- Install exhaust manifolds using new gaskets and fasteners.
See
180 Exhaust System.
- Refill and bleed cooling system as described in 170 Radiator
and Cooling System.
- Change engine oil and filter as described in 020 Mainte.
nance.
CA UTIOW-
To prevent damaging engine electricalsystems, be sure to in-
stall all ground wires previously removed.
Tightening
tOrqUeS
Camshaft sprocket to camshaft 15 Nm (1 1 ft-lb)
Coolant manifold to cylinder head lo Nm (7.5 It-lb)
Cylinder head cover nuts 10 Nm (7.5 ft-lb)
Exhaust manifold to head 22 Nm (17 ft-lb)
Engine mount to subframe 42 Nm (30 ft-lb)
Spark plugs to cylinder head 22 Nm (17 ft-lb)