engine BMW 540i 1998 E39 Workshop Manual

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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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113-8
[cylinder Head Removal and Installation 1
Cylinder leak-down test
The most conclusive diagnosis of low compression symp-
toms requires a cylinder leak-down test. Using a special
tester and compressed air, each cylinder, in turn, is pressur-
ized. The rate at which the air leaks out of the cylinder, as well
as where the air leaks out, can accurately pinpoint the magni-
tude and location of the leakage.
Before attempting any repair that requires major engine dis-
assembly, use a leak-down test to confirm low compression.
~YL~NDER HEAD REMOVAL AND
~NSTALLATION (M52 ENGINE)
WARNING-
Due to rislc of personal fnjur~: be sure the engine is cold be-
fore beginning the removal procedure.
Cylinder head removal and installation is a time consuming
repair procedure requiring multiple special
service tools.
Read the entire procedure before beginning the repair.
This procedure includes the following steps:
Cylinder head, removing,
M52 engine
Cylinder head, installing,
M52 engine
Cylinder head, removing, M52 engine
- Disconnect negative (-) cable from battery in luggage com-
partment.
CAUTION-
Prior to disconnecting the battea read the battery discon-
nection cautions in 001 General Cautions and Warnings.
-

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11 3-9
Cylinder Head Removal and Installation
< Remove left and right interior ventilation ducts (left shown):
Release ventilation filter cover latch (A) and remove cover.
Release plastic locking tab
(6) or release locking tabs on
top of duct (later models).
Rotate duct counterclockwise to unlock from bulkhead and
remove (arrow).
Disconnect electrical connector from hood switch
(C).
Release spring lock (D).
Slide filter housing away from inner fender to remove.
Removal of right side ventilation duct is similar.
Remove rear bulkhead panel: Remove rubber sealing
gasket (arrow).
0 Remove 3 mounting clips (A).
Remove
4 retaining screws (6).
Lift out panel.
< Remove complete air filter housing:
Loosen
intake duct hose clamp (A) at throttle assembly.
Loosen clamp and remove idle control hose from
~ntake
duct (6) and disconnect Idle speed control valve electr~cal
harness connector.
Disconnect
electr~cal harness connector (C) from mass alr
flow sensor.
Remove air filter housing mounting screw (D).
Disconnect vent tube
(E).
Loosen air intake duct clamp (F).
Carefully lift air filter housing out of engine bay.
4 Remove positive battery cable and intake manifold cover:
Remove protective cover from positive (+)jumper post (A).
Loosen and remove battery lead mounting nut.
Remove battery lead and push down through intake mani-
fold.
Remove trim caps (arrows) from fuel injector cover.
Remove cover hold down fasteners and lift off cover.

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113-10
Cylinder Head Removal and Installation
4 Working above engine, disconnect the following:
Vent line from cylinder head cover
(A).
. Oxygen sensor connectors (B).
Electrical harness connector from VANOS solenoid
valve
(C).
Electrical harness connectors at throttle valve position
switch
(D), ASC valve position switch (E), fuel injector har-
ness
(F) and vent valve (G).
CAUTION-
Be sure to mark oxygen sensor harness connectors so that
they can be reassembled correctly Do not interchange con-
nectors.
4 Where applicable, remove schraeder valve cap (arrow) from
air connection on fuel rail. Using a tire chuck, blow fuel back
through feed line using a brief burst of compressed air (max-
imum of
3 bar or 43.5 psi).
WARNING-
. Fuel in fuel line is underpressure (approx. 3 - 5 bar or 45 -
75 psi) and may be expelled. Do not smoke or work near
heaters or other fire hazards. Keep a fire extinguisher
handy Before disconnecting fuel hoses, wrap a cloth
around fuel hoses to absorb any leaking fuel. Catch and
dispose of escaped fuel. Plug open fuel lines.
- Always unscrew the fuel rank cap ro release pressure
;n the tank before working on the tank or lines.
Disconnect fuel lines by sliding locking collar in (arrows) and
pulling lines apart.
NOTE-
BMW uses three styles of fuel line connections; a one-time
use
clamp; a locking fitting that uses BMWspecial tool 16 1
050 to release; and a quick release sleeve (above) that dis-
connects the line when depressed.

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..
Cylinder Head Removal and Installation 1
< Remove intake throttle valve and ASC throttle assemblies:
Disconnect ASC throttle cable
(A).
- Remove ASC throttle housing mounting fasteners (B).
NOTE-
It is not necessary to disconnect coolant hoses (C) 01
bowden cables (D).
Remove intake throttle housing mounting hardware, pull
throttle housing off
intake manifold, and set aside.
- Working under intake manifold, disconnect the following:
Engine oil dipstick tube support.
Oil separator return line from dipstick tube.
Intake air temperature sensor electrical harness connector
(underside of intake manifold near throttle body).
* Fuel tank vent line and electrical harness at canister vent
valve.
Remove lower intake manifold supports (arrows).
- Disconnect coolant line retaining bracket at cylinder block.
4 Remove manifold mounting hardware (arrows).
- Remove intake manifold from cylinder head while carefully
checking for electrical connections or hoses.
NOTE-
Fuel rail is removed with intake manifold,
CAUTIOI\C
Stuff clean rags into open intake ports to prevent any parts
from falling into
Nie engine intake.
- Drain cooling system (engine block and radiator), then re-
move radiator cooling fan and fan shroud. See
170 Radiator
and Cooling System.
- Disconnect coolant hoses from thermostat housing.

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-
Cylinder Head Removal and Installation c
q Remove secondary air inject~on check valve (arrow).
4 Remove cylinder head top cover:
Remove plastic trim caps (arrows).
Remove engine oil filler cap.
Remove cover hold down fasteners and lift off cover.
4 Remove ignition coils:
Disconnect ignition coil harness connectors.
. Remove coil mounting fasteners.
Remove coils.
Remove ground straps.
NOTE-
Make note of ground wire at mounting studs arrangement
during removal.
- Remove sparlc plugs.
- Remove cylinder head cover mounting fasteners and remove
cylinder head cover.
NOTE-
The cylinder head cover mounting bolt insulators and gas-
lets should be reinstalled in their original locations. Make
note of their arrangement during removal.

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- - , -. I Cylinder Head Removal and lnstallatio~
4 Remove oil baffle cover from above intake camshaft.
4 Unscrew and remove three cylinder head cover studs (ar-
rows)
at rear of cylinder head.
Set engine to approximate top dead center
(TDC) by turning
crankshaft bolt in direction of rotation (clocltwise when
viewed from front of engine) until camshaft lobes for cylinder
1 face each other (dotted lines) and arrows on camshaft
sprocltets face up.
- Set engine to TDC by aligning "OIP mark of vibration damp-
er with boss cast on lower timing chain cover.
< Lock cranltshaft at TDC:
Remove sealing plug from bore on lower left side of engine
block below starter. Secure crankshaft in
TDC position with
BMW special tool 11 2 300.

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11 3-1 4
Cylinder Head Removal and Installation
4 Secure camshafts in TDC position using BMW special tool
set
11 3 240.
4 Remove access plugs from VANOS control unit in front of
exhaust camshaft sprocket.
Remove
4 bolts (arrows) from exhaust camshaft sprocket
(Torx E10).
CAUTION-
Hold the camshaft stationary (at hex on camshaft) when loos-
eninq or tiqhteninq sprocl(et mounting fasteners. r
Press down on secondary chain tensioner and lock into place
using
BMW special tool 11 3 292 or a similar size pin.
NOTE-
Some tensioners may have a single hole for special tool.
Remove secondary chain tensioner.
Disconnect harness connector and oil line fitting from bottom
of VANOS control unit.
NOTE-
Wrap the VANOS oil line fitting with a shop rag to absorb
leaking oil.
Remove VANOS control unit mounting nuts and bolt at front
of cylinder head.

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Cylinder Head Removal and Installation / -
< Use a spanner tool to rotate exhaust sprocket until stop on in-
take sprocket is contacted.
- Slide VANOS control unit forward to remove
Remove primary chain tensioner (arrow)
WARNING -
Remove tensioner slowly - it is under spring pressure. I
- Working at the intake side of cylinder 1 :
Detach electrical harness connector for camshaft position
sensor and remove sensor.
Detach electrical harness connector for coolant tempera-
ture sensor.
- Remove exhaust manifolds. D~scard nuts. See 180 Exhaust
System.
Disconnect heating system hoses (arrows) from back of cyl-
inder head.

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113-16
Cylinder Head Removal and Installation
- Remove secondary timing chain and sprockets:
Remove mounting nuts from front of intake camshaft
sprocket. Remove and label shim.
CAUTION-
Hold the camshaft stationary (at hex on camshaft) when loos-
ening or tightening sprocket mounting fasteners.
Remove mounting nuts from front of exhaust camshaft
sprocket and remove and label thrust washer.
NOTE-
Where applicable, make note of thrust washerpositions. The
thicker
(0.4 mm) washer is mounted outermost.
- Remove secondary sprockets together with camshaft tim-
ing chain from front of camshafts.
CAUTION-
The camshafts must be locledin the TDCposition using the
special service tool as described earlier: The arrows on the
sprockets should not be used to accurately set the engine to
TDC. The tool holds the camshafts parallel to each other and
NOTE-
Do not remove the sprocl parts are being replaced. Wire tie each sprocket to the chain
to
Iceep the sproclefs timed to each other:
CAUTIOI\C
The crankshaft must not be allowed to rotate once the cam-
shaft timing chain is removed. The pistons can
contact the
valves.
Unscrew timing chain guide and remove.
Lift off primary sprocket with chain.
Secure chain with wire to prevent chain from dropping into
lower timing cover.
Unscrew timing case cover to cylinder head bolts (arrows).
NOTE-
Photo shows timing chain guide in place; it should first be re-
moved as described previously.
Remove crankshaft locking tool
(BMW special tool 11 2 300).
Using the crankshaft vibration damper bolt, turn engine op-
posite of normal direction of rotation (counterclocltwise as
viewed from the front) approximately 30". This prevents ac-
cidental contact between valves and pistons during installa-
tion.