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020-1 6
Maintenance
loose, hose is damaged, or connection is dirty or corroded.
Dried coolant has achalky appearance. Hoses should be firm
and springy. Replace any hose that is cracked, has become
soft and limp, or has been contaminated by oil.
4 As a preventive measure, replacement of the cooling system
hoses every four years is recommended. The illustration
shows examples of damage to coolant hoses. Any of these
conditions is cause for replacement (illustration courtesy of
/ Abrasion Damaged Hose Heat Damaged Hose 1 Gates Rubber Company, I~c.).
Engine drive belt, replacing
Drive belts and pulleys transfer power from the engine crank-
shaft to various accessories.
E39 models use two polyribbed
(serpentine) belts:
The outer belt turns the
NC compressor.
0 The inner, longer belt turns the alternator (generator), cool-
ant pump and power steering pump.
Inspect drive belts with the engine off. If the belt shows signs
of wear, cracking, glazing, or missing sections, it should be
replaced
immediately. To reduce the chance of belt failure
while driving, replacement of the belts every four years is
recommended.
WARNING -
Observe care when replacing belts. Personal injury could
result if a tensioner springs back into position uncontrolled.
CA UTIOI\C
Mark drive belt rotation direction if removing and reusing an
old belt.
NOTE-
When belts are replaced with new ones, store the old set in
the trunk for emergency use.
All models, use
BMW special tools 11 5 030 and 11 5 040 to
loosen and remove cooling fan and clutch from coolant
pump.
NOTE-
32 mm cooling fan nut has left-hand threads
If necessary, remove fan cowl from radiator.
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Maintenance
< Remove NC compressor belt:
Loosen tensioner mounting fasteners (arrows)
Swing tensioner down to remove belt.
4 To reinstall compressor belt:
Route belt over pulleys.
* Pretension belt by turning adjuster clockwise (arrow) to
stop.
- Tighten tensioner mounting bolts (A).
Tightening torques
Fan clutch to coolant pump (left- hand thread)
with BMW tool
11 5 040
30 Nm (22 ft-lb)
without BMW tool 11 5 040
40 Nm (29 ft-lb)
Tensioner to engine block
8.8 grade
22 Nm (16 ft-lb)
10.9 grade (Ilquid-cooled alternator) 30 Nm (22 ft-lb)
Idle speed
Engine idle speed can change due to a number of factors, in-
cluding normal wear. The idle speed is electronically adaptive
and not adjustable. See
130 Fuel Injection for more informa-
tion.
Catalytic converter and oxygen sensors
OBD II enhanced emission standards require the engine
control module (ECM) to monitor the oxygen content in the
exhaust with oxygen sensors placed before and after the cat-
alytic converter. This allows for tighter control of tail pipe
emissions and also allows the ECM to diagnose converter
problems. If the ECM detects that catalytic converter or oxy-
gen sensor efficiency has degraded past a certain
prepro-
grammed limit, it will turn on the malfunction indicator light
(MIL), and store a diagnostic trouble code (DTC) in the ECM.
See OBD On-Board Diagnostics for more information on
OBD
ll systems.
Replacement of oxygen sensors at the specified intervals
he engine and emission control system will
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Engine Removal and Installation
4 Working at E-box at right rear of engine compartment:
Disconnect engine electrical harness connectors
(arrows).
Lift off harness looms and lay over engine.
- Remove polyribbed drive belts. Mark direction of rotation if
belts will be reused. See 020 Maintenance.
- Remove exhaust system and transmission from car. See 180
Exhaust System, 230 Manual Transmission or 240 Auto-
matic Transmission.
NOJE-
Detach automatic transmission cooler lines from radiator, re-
move brackets holding lines to side of engine, andstore lines
in a clean environment.
- Remove power steering pump:
If necessary, remove steering pump pulley.
Remove front and rear pump mounting bolts.
Suspend pump from body using stiff wire.
4 Remove A/C compressor mounting bolts (arrows) and AIC
compressor from its mounting bracketwithoutdisconnecting,
distorting, or deforming any refrigerant lines. Suspend from
body using stiff wire.
4 If applicable, remove secondary air pump:
Remove hose at one-way valve
(A).
Remove bolts at support bracket on strut tower (arrows).
- Disconnect electrical harness from bottom of secondary
air pump.
Remove bracket from strut tower.
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--
-- Engine Removal and installation' -
Remove polyribbed A/C compressor belt:
Mark direction of belt travel if belts are to be reused.
Loosen bolts
(A).
Turn adjusting lug (B) clocltwise to release belt tension.
Working beneath car, remove power steering pump and air
conditioner compressor. Suspend from body using stiff wire.
Remove exhaust manifolds. See
180 Exhaust System.
< lnstall engine lifting device (BMW 11 0 000 or equivalent) to
front and rear engine supports and raise engine until it's
weight is supported. Detach engine mounts.
a Watch carefully for hoses and electrical wires that might
snag.
- installation is reverse of removal:
Replace all gaskets, O-rings and seals.
V-8 engine mounts have two sets of mounting holes. E39
cars use front most mounting holes.
* On cars with automatic transmission, use new O-rings at
ATF cooler lines.
Use new alignment sleeves when installing transmission.
Be sure engine drive belts properly engage pulley grooves.
When installing belt, preload tensioner to stop (toward
belt), then tighten tensioner clamping nut.
lnstall front exhaust pipes using new gasltets and copper
paste and new mounting hardware. See
180 Exhaust
System.
Change engine oil and filter. Check all other fluid levels as
described in
020 Maintenance.
Refill and bleed cooling system as described in
170 Radi-
ator and Cooling System.
CAUTION-
Do not interchange knoclc sensor harness connectors. Seri-
ous engine damage may result
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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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Camshaft Timing Chain Timing chains, removing
(M52 engine)
Camshaft timing chain removal on M52 engines requires en-
gine oil pan removal.
Special
BMW sewice tools are needed for timing chain re-
moval and installation procedures. The special tools assure
propertiming of thevalvetrain. Precise marks to
setthe timing
on the camshafts are not provided for reassembly. Read the
procedures through before beginning the job.
NOTE-
If the camshafts are not properly timed, the pistons can con-
tact the valves.
- Remove VANOS control unit. See VANOS control unit, re-
moving (M52 engine).
- Remove radiator cooling fan and shroud. See 170 Radiator
and Cooling System.
- Drain cooling system. See 170 Radiator and Cooling Sys-
tem.
- Remove coolant hoses from thermostat housing and remove
thermostat housing from front of cylinder head.
- Loosen bolts for coolant pump pulley.
- Remove drive belts for alternator and AIC compressor. See
020 Maintenance.
- Remove coolant pump pulley.
Remove drive belt tensioner mounting bolts (arrows) and re-
move tensioner from front of engine.
- Remove engine speed sensor from lower timing chain cover.
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-
Camshaft Timing chain1
4 Remove oil lines from camshaft supports (arrows).
- Remove radiator cooling fan and fan shroud. See 170 Radi-
ator and Cooling System.
NOTE-
The radiator cooling fan nut (32 mm wrench) has left-hand
threads.
- Remove engine drive belts alternator and AlC compressor.
See
020 Maintenance.
4 Remove vibration damper bolts (arrows) and remove
damper.
4 Mount BMW special tool 11 2 450 to crankshaft hub while
aligning damper locator pin with hole (arrow) in special tool.
CAUTION-
Crankshaft center bolt is torqued to 410 Nm (300 ft-lb) use
BMWspecial tool I I 2 450 to secure crankshaft when remov-
ing center bolt.
- Loosen and remove cranltshaff center bolt.
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Fuel Injection
- Ignition:
Direct ignition
Knock control
4 Primary1 secondary ignition monitoring
- Emissions:
OBD II compliance
Secondary air injection
Pre- and post-catalyst oxygen sensors
0 Electrically heated DME-mapped thermostat
Misfire detection
Evaporative emission control and
leak detection
Malfunction indicator light (MIL)
Performance controls:
Dual VANOS control
Output of injection signal (TI) for fuel economy gauge
Output of engine rpm (TD) for tachometer
AIC compressor control
0 Electric radiator cooling fan
CAN-Bus communication
Stability and traction system
(ABSIASCIDSC) interlace
Electronic immobilizer (EWS)
Cruise control
ECM programming