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Fuel Tank and Fuel Pump
Warnings and cautions
Observe the following warnings and cautions when servicing
the fuel system.
WARNING-
* The fuel system is designed to retain pressure even when
the ignition is off. When working with the fuelsystem, loos-
en the fuel lines slowly to allow residual
fuel pressure to
dissipate. Avoid spraying fuel. Use shop rags to capture
leaking fuel.
Before beginning any work on the fuel system, place a
fire extinguisher in the vicinity of the work area.
Fuel is highly flammable. When working around fuel, do
not disconnect any wires that could cause electrical
sparks. Do not smoke or worknearheaters or other fire
hazards.
* Always unscrew the fuel tank cap to release pressure
in the
tanlc before working on the tank or lines.
When disconnecting a fuel hose, wrap shop rag around
end of hose to prevent spray of fuel under pressure.
Do not use a work light with an incandescent bulb near
any fuel. Fuel may spray on the hot bulb causing a fire.
0 Make sure the worlc area is properly ventilated.
CAUTION-
- Prior to disconnecting the battery, read the battery discon-
nection cautions given in
001 General Cautions an4
Warnings.
Before
making any electrical tests with the ignition
turned on, disable the ignition system as described in
120 Ignition System. Be sure the battery is discon-
nected when replacing components.
To prevent damage to the ignition system or other DME
components, including the engine control module
(ECM), always connect and disconnect wires and test
equipment with the ignition off.
Cleanliness is essential when
worl~ing with the fuel sys-
tem. Thoroughly clean the fuel line unions before dis-
connecting any of the lines.
Use only clean tools. Keep removed parts clean and
sealed or covered with a clean, lint-free cloth, especial-
ly if completion of the repair is delayed.
Do not move the car while the fuel system is open.
Avoid using high pressure compressed air to blow out
lines and components. High pressure can rupture inter-
nal seals and gaskets.
Always replace seals, O-rings and hose clamps.

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Fuel Tank and Fuel Pump 1
Activated carbon canister I fuel tank leak
detection unit
(LDP or DMTL), removing . . -
and installing
- Raise rear end of car and support safely.
CAUTION-
Make sure the car is stable and well supported at all times.
Use a professional automotive lift
orjack stands designed for
the purpose.
A floor jack is not adequate support.
- Remove left rear wheel and inner fender panel
Remove carbon canisterlfuel tank leak detection unit
(V-8 model shown):
Disconnect electrical harness connector
(A) from fuel tank
leak detection unit.
Pinch and remove quick-disconnect fittings at intake line to
air filter housing
(5) and hose to expansion tank (C).
* Remove mounting clamp and lower canister with fuel tank
leak detection unit.
Installation is reverse of removal.
Tightening
torques
Hose clamp 8 - 13 mm dia. 2 Nrn (18 in-lb)
Hose clamp
13 - 16 rnm dia 3 Nm (27 in-lb)
Running losses (312-way) valve,
removing and installing
The running losses (312-way) valve is located under the car
beneath the driver's seat, just ahead of the fuel filter. A protec-
tive covershieldsfuel system components from road hazards
and dirt.
The engine control module
(ECM) controls the operation of
the 312-way valve (pulse-width modulated). On engine start
up, the valve solenoid is energized for 20 seconds in order to
supply full fuel volume to the fuel rail.
After20 seconds, the
solenoid is deactivated and sprung closed (the bypass is
opened). This reduces the amount of fuel circulating through
the fuel rail and diverts the excess to return to the fuel tank
through the fuel pressure regulator.
The fuel injectors are supplied with pressurized fuel, but ex-
cess fuel is diverted to the fuel tank without first passing
through the fuel rail. This prevents the excess fuel from ab-
sorbing heat in the engine compartment, thus lowering the
temperature and amount of vaporization in the fuel tank.

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170-8
I Radiator and Cooling System
Common cooling system faults can be grouped into one of 4
categories:
Cooling system
lealts
Poor coolant circulation
Radiator cooling fan faults
Electrical/electronic faults
Cooling system inspection
- Check that coolant pump drive belt tensioner is functioning
properly and that belt tension is correct. Belt tensioner sys-
tems for the different models are shown in
020 Maintenance.
- Check condition of coolant pump drive belt.
- Checlc coolant hoses for cracks or softness. Checlc clamps
for looseness. Check coolant level and check for evidence of
coolant
lealts from engine.
- Check that radiator fins are not blocked with dirt or debris.
Clean radiator using low-pressure water or compressed air.
Blow outward, from engine side out.
- To check coolant pump:
Remove mechanical cooling fan. See Mechanical
(vis.
cous clutch) cooling fan, removing and installing.
Remove drive belt from coolant pump pulley. See
020
Maintenance.
Firmly grasp opposite sides of pulley and check for play in
all directions.
Spin pulley and check that shaft runs smoothly without
play.
NOTE-
The coolant provides lubrication for the pump shaft, so an oc-
casional drop of coolant
lealing from the pump is acceptable.
If coolant drips steadily from the vent hole, replace the pump.
- At normal engine operating temperature, cooling system is
pressurized. This raises boiling point of coolant.
Leaks may
prevent system from becoming pressurized. If visual evi-
dence is inconclusive, pressure test cooling system as de-
scribed later to help pinpoint hard-to-find leaks.
- If cooling system is full of coolant and holds pressure:
- Use an appropriate scan tool to interrogate engine control
module (ECM) for radiator fan or DME control circuit faults.
Checlc for loose or worn drive belt.
0 Test for failed thermostat or coolant pump impeller. Some
pumps may be fitted with plastic impellers.

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Radiator and Cooling systeml
Tightening torques
Block drain plug to block 25 Nm
(18
it-lb)
Coolant hose clamp (32 - 48 2.
5 Nm (22 in-lb)
mm hose diameter)
Radiator drain plug to radiator
2-3Nm(l8-27in-lb)
Thermostat housing to cylinder
head 10 Nm (89 in-lb)
I Coolant thermostat housing assmbly- - I
Thermostat, removing and installing
(M52 TU or M54 engine)
4 The electric map-controlled thermostat is part of the thermo-
stat housing at the front of the cylinder head.
1. Bolts (M6)
2 Bolt (ME)
3. Housing with thermostat
4. Gasket
- If a faulty thermostat is suspected, use appropriate scan tool
to interrogate
ECM for stored fault codes.
- Drain radiator and engine block. See Coolant, draining and
filling (6-cylinder models).
CAUTION-
Allow cooling system to cool before opening or draining the
system.
- Remove cooling fan and fan shroud. See Mechanical (vis-
cous clutch) cooling fan, removing and installing.
- Disconnect electrical harness connector from thermostat
housina.
4 Lever out retaining clips (arrows) and pull hose fittings off
thermostat housing.
- Unbolt and remove thermostat housing from front of engine.
Loosen nut at top of engine lifting eye to facilitate removal.
- Installation is reverse of removal, noting the following:
Keep sealing faces free of oil.
* Use new sealing gasket.
When reinstalling hose to thermostat housing, install clip
on hose end fitting, then push hose onto housing until it
clicks into place.
Fill system with coolant. See Coolant, draining and fill-
ing (6-cylinder models).

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Tightening torques Block drain plug to block
25 Nm (18 ft-lb)
Radiator drain plug to radiator 2 - 3 Nm (18 - 27 in-lb)
Thermostat housing to
cylinder head 10 Nm (89 in-lb)
Thermostat, removing and installing
(V-8 models)
The electrically-heated thermostat is an integral parl of the
thermostat housing. The operation of the thermostat is moni-
tored by the engine control module (ECM).
- If a faulty thermostat is suspected, use appropriate scan tool
to interrogate ECM for stored fault codes.
- Drain radiator and engine block. See Coolant, draining and
filling
(V-8 models).
WARNING -
Allow cooling system to cool before opening or draining the
system.
- Disconnect mass air flow (MAF) sensor electrical harness
connector. Remove air intake duct together with MAF sensor.
- Remove mechanical cooltng fan and fan shroud. See Me-
chanical (viscous clutch) cooling fan, removing and
in-
stalling.
Disconnect electrical harness connector (arrow) from ther-
mostat housing.
Remove coolant hose from thermostat housing.
NOTE-
M62 engine: Hose is clamped on.
M62 TU engine: Hose is attached with quick-disconnect fit.
ting. Remove clip to disconnect hose.

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Steering and Wheel Alignment
Pitman arm, adjusting
As the vehicle suspension settles down, the toe on the left
and right wheels must remain identical for proper handling.
By adjusting the height of the
pitman arm, the left and right tie
rods are moved to the same ride level setting. This will opti-
mize straight-ahead travel on uneven road surfaces.
- Raise front of car. Remove splash shield from under engine.
WARNING-
Male sure the car is iirmly supported on jack stands de-
signed ior the purpose. Place jack stands beneath structural
chassis points. Do not place
jaclc stands under suspension
parts.
- Remove bolts from left and right inner control arm mounts.
Place
BMW special tool 32 2 140 through right side control
arm mounting bolt hole.
Loosen fastener
A and push pin El up so that it is firmly
against tie rod
(arrow). Tighten fastener A.
- Remove tool without disturbing position of pin El.
- Loosen pitman arm clamping bolt and slide arm up.
4 Place special tool 32 2 140 through left side control arm
mounting bolt hole.
Slide
pitman arm up or down until tie rod makes contact
with pin
(El).
Tighten pitman arm clamping bolt.
Tie rod height differences
Deviation between
left and right tie rod height -?-I .5 rnrn (LO6 in)

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320-34
I Steerins and Wheel Alignment
Front toe and toe difference angle
Toe is the difference in the distance between the front of the
front wheels and the rear of the front wheels. It is adjusted by
altering the length of the tie rods.
Toe difference angle determines the progressively different
paths taken by the front wheels as the car is turning. In
V-8
models, it is set by the pitman arm adjustment, but depends
on accurate setting of the toe.
Toe adjustments should only be made on specialized align-
ment equipment and only with the car in normal loaded posi-
tion, described below.
- Set front wheel toe at tie rod ends:
4 6-cylinder models: Loosen tie rod lock nut (A).
Adjust toe by turning inner tie rod (B) to change length
- V-8 models: Loosen left and right tie rod clamp bolts.
Adjust toe by turning inner tie rod to change length.
NOTE-
* Steering rack or steering gearbox can be centered by
aligning centering mark on steering shaft
with lug on steer-
ing rack.
To keep steering wheel centered, adjust both tie rods equal
amounts.
&cylinder models: Make sure the rubber boot on the rack
moves freely on the tie rod and does not become twisted.
Tightening torques
Tie rod clamp bolt
Tie rod collar
nut
27 Nm (20 ft-lb)
45 Nm (33 A-lb)
Rear toe
To adjust rear wheel toe, turn eccentric inner mounting bolt in
upper front control arm (traction strut).
NOTE-
Always adjust rear camber first.
- Before making toe adjustment, install new
mounting nut and tighten.
- Loosen nut one-half to one full turn.
4 Turn eccentric bolt (arrow) to adjust toe. rear
control arm

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Brakes
Brakes, bleeding
The procedure below requires a BMW Service Tester (DIS-
pluslGTl/MoDiC).
- Determine type of traction control (ASC, DSC with precharge
pump, DSC without precharge pump). Be sure to use correct
specification brake fluid, according to application table below.
Brake fluid applications
ABS I ASC and ABS / DSC models DOT 4 brake fluid
with precharge pump (to 911998)
ABS I DSC models without precharge DOT 4 low viscosity
pump (911998 and later) brake
fluid
< Remove left side interior ventilation microfilter housing:
Remove upper cover and microfilter loclting clip
(A).
Release locking clamp (B), and rotate air tube in direction
of arrow to remove.
Disconnect wiring harness from hood switch
(C).
Release filter body mounting clamp (D) and remove lower
microfilter housing.
- Top off bralte fluid in reservoir and connect BMW Service
Tester to
20 pin Data Link Connector (DLC) under hood or 16
pin
DLCIOBD I1 connector under dash.
- Call up service function Bleeding ABS / ASC or service func-
tion Bleeding ABS
/ DSC, depending on installed system.
- Fill pressure bleeding device with the correct brake fluid and
connect to brake fluid reservoir and apply pressurize.
Do not exceed a pressure of
2 bar (29 psi) when pressure
bleeding the
brake system. Excessive pressure will damage
4 Starting at right rear wheel, connect bleed hose and fluid re-
ceptacle to bleeder screw (arrow).
CA UTlON-
Bleeder hose must always remain submersed in clean brake
fluid whenever the bleeder valve is open.