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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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170-1 6
I Radiator and Cooling System
- Remove fan and fan shroud mounting fasteners. Slide fan
and fan shroud downward to remove.
- Reinstallation is reverse of removal.
Thermostat, removing and installing
(M52 engine)
The coolant thermostat is installed in a housing at the front of
the engine.
- Drain coolant from radiator and engine block. See Coolant,
draining and filling (6-cylinder models).
WARNING -
Allow the cooling system to cool before opening or draining
the system.
- Remove mechanical cooling fan and fan shroud. See Me-
chanical (viscous clutch) cooling fan, removing and in-
stalling.
- Disconnect coolant hoses from thermostat housing.
- Remove thermostat housing from front of engine.
- Remove thermostat. Note thermostat direction and orienta-
tion before removing.
- Installation is reverse of removal, noting the following:
- Use new O-ring and gasket(s) when installing thermostat
and housing.
NOTE-
Some thermostats have a direction arrow or vent hole near
the edge. Install the thermostat so that either the arrow or
hole are at the top.
Fill system with coolant as described in Coolant, draining
and filling (6-cylinder models).
CAUTION-
Be sure to reconnect ground wire@) at thermostat housing
mounting bolt, where applicable.
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180-2
Exhaust System
The exhaust system is designed to be maintenance free, al-
though regular inspection is warranted due to the harsh oper-
ating conditions. Under normal conditions, the catalytic
converter does not require replacement unless it is damaged.
New fasteners, clamps, rubber mounts and gaskets should
be used when replacing exhaust components.
A liberal appli-
cation of penetrating oil to the exhaust system nuts and bolts
in advance may make removal easier.
WARNING -
The exhaust system and catalytic converter operate at
very high temperatures. Allow components to cool before
servicing. Wear protective clothing to prevent burns.
Do not use flammable chemicals near a hot
cataiyiic
converter.
Corroded exhaust system components crumble easily
and often have exposed sharp edges. To avoid injury,
wear eye protection and heavy gloves when working
Exhaust system, removing and installing
The removal and installation procedures given here are gen-
eral procedures for all models. The removal of the exhaust
system as a complete unit is recommended. Once the com-
plete system is removed from the car, individual pipes and
mufflers can be more easily replaced.
WARNING-
Exhaust gases are colorless, odorless, and very toxic. Run
the engine only in a well-ventilated area. Immediately repair
any
leaks in the exhaust system or structural damage to the
car body that
might allow exhaust gases to enter the passen-
ger compartment.
CAUTION-
Use care not to drag or bang oxygen sensors. Oxygen sen-
sors can be easily ruined.
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- Raise and safely support vehicle
WARNING-
Make sure the car is stable and well supporied at all times.
Use a professional automotive /iff orjack stands designed for
the
ournose. A floor jack is not adeouate suooort.
- If necessary, remove transmission splash shield.
- Disconnect fluid line from slave cylinder on lefl side of trans-
mission. Place pan under hose to catch dripping fluid.
4 Working underneath transmission, remove slave cylinder
mounting nuts (arrow) from clutch housing and remove
cylinder.
- Installation is reverse of removal, noting the following:
Check for wear on slave cylinder. Any wear except on tip is
caused by misalignment of clutch components.
Lightly coat
pushrod tip with molybdenum disulfide grease
(MolyltoteIB Longterm or equivalent).
. During installation be sure pushrod tip engages recess in
clutch release lever.
Fill fluid reservoir with clean fluid.
. Bleed clutch hydraulics as described earlier.
Tightening
toraues - -.
Clutch slave cylinder to transmission 22 Nm (16 R-lb)
Fluid line to slave cylinder 17 Nm (13 ft-lb)
The transmission must be removed from the engine to access
the clutch mechanical components. It is recommended that
the clutch disc, pressure plate and release bearing be re-
placed during a clutch overhaul.
Besure tocheck the bottom of the bellhousing foroil. If engine
oil is found, check for a faulty rear crankshaft main oil seal.
See
119 Lubrication for rear main seal replacement.
Clutch variations
Two versions of the clutch are used:
1997 528i (6 cylinder) uses traditional clutch components.
All
540i (V-8) and 1998 and later 6 cylinder models from
use a self-adjusting clutch (SAC).
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240-2
/ ~utomatic Transmission
This section covers maintenance and replacement of the
automatic transmission for
E39 models.
Automatic transmission internal repairs are not covered.
Such repairs require special service equipment and knowl-
edge. If it is determined that transmission internal
sewice is
required, consult an authorized BMW dealer about a factory
reconditioned unit or a transmission rebuild.
CAUTION-
ATF does not circulate unless the engine is running. When
towing an automatic transmission vehicle, use a flat bed truck
or raise the rear wheels off the ground.
Special tools
Some special tools are required for the removal and installa-
tion of an automatic transmission on the
E39 BMW models.
While these tools are not absolutely necessary, they are es-
pecially helpful when dealing with the removal and replace-
ment of the torque converter.
4 Engine support bracket
(Tool No. BMW
00 0 200.00 0 208)
4 Transmission jack
(Tool No.
BMW 00 2 030)
4 Engine support block (V-8 models) 11 7310 (Tool No. BMW 11 7 310)
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300-1 0
/Suspension, Steering and Brakes - General
The steering system features variable power assist provided
by an engine-driven hydraulic pump.
Rack and pinion steering
6-cylinder models
(525i, 5281, 5300
Two types of steering systems are used in E39 models. 6-
cylinder (525i, 5281, 530i) models are equipped with a steer-
ing rack system. V-8
(540i) models are equipped with a re-
circulating ball and nut steering gearbox.
Rack-and-pinion steering
Steering components in 6-cylinder models consist of a rack-
and-pinion type steering gear and connecting linltage to the
road wheels.
The steering linkage connects the rack-and-pinion unit
through tie rods to the steering knucltles. The tie rod ends al-
low the wheels to pivot and react to suspension travel.
Recirculating ball and nut steering
V-8 models
(540i)
I
Recirculating ball and nut steering
Recirculating ball and nut steering in V-8 models consists of a
steering box with integrated hydraulic control valve and con-
necting linkage to the road wheels.
Thesteering linkageconnects the steering gearbox through a
pitman arm to the wheels. An idler arm maintains correct toe
angle. The tie rod allow the wheels to pivot and react to sus-
pension travel.
E39 cars are equipped with power disc brakes with integral
antilock brakes (ABS). The parking bralte is a dual-drum sys-
tem integrated with the rear brake rotors.
Power assist is provided by a vacuum booster when the en-
gine is running. The brake pedal
pushrod is connected direct-
ly to the master cylinder, so failure of the vacuum booster
does not normally result in total
bralte failure.
Each disc bralte uses a caliper with a single hydraulic cylin-
der. Brake pads in the left front and right rear contain wear
sensors. When brake pads need replacement, the sensors il-
luminate a light on the dashboard.
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Steering and Wheel Alignment
Steering system warnings and cautions
WARNING -
The BMW airbag system is complex. Special precautions
must be observed when servicing the system. Serious in-
jury may result if system service is attempted by persons
unfamiliar with the BMW
airbag system and its approved
service procedures. BMW specifies that all inspection and
service should be
peiformed by an authorized BMW deal-
e,:
The BMW E39 is equipped with an airbag mounted in
the steering wheel. The
airbag is an explosive device
and should be treated with extreme caution. Always fol-
low the
airbag removal procedure as outlined in 721
Airbag System (SRS).
BMW airbags are equipped with a bacli-up power sup-
ply inside the
airbag control module. A 5 second wait-
ing period should be observed after the battery cable
has been disconnected. This will allow the reserve
power supply to discharge.
Do not reuse self-locking nuts. They are designed to
be used only once and may fail if reused. Always re-
place them with new locliing nuts.
* Do not install bolts and nuts coated with undercoating
wax, as correct tightening torque cannot be assured.
Always clean the threads with solvent before installa-
tion, or install new parts.
Do not attempt to weld or straighten any steering com-
ponents. Always replace damagedparts.
CAUTION--
- Some E39 models are equipped with aluminum suspen.
sion components. The following cautions apply:
Due to the chemical and corrosion characteristics of
aluminum, do not bring into contact with battery acid.
Do not clean with wire brushes with brass or iron bris-
tles. Only use brushes with stainless steel bristles.
Do
not expose to flying sparks from grindinghutting op-
erations.
Do not subject to steel welding splashes.
* Do not expose to temperatures over 80% (176°F).
even for short periods. Temperatures in painting iacili-
ties are not a problem.
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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