
Downloaded from www.Manualslib.com manuals search engine
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.

Downloaded from www.Manualslib.com manuals search engine
020-1 8
Maintenance
V-8 engine drive belt diagram (NC belt not shown).
NOTE-
Two types of belt tensioners are used on the V-8 engines.
The tensioner shown in this procedure is for cars built up to
8/97. The later style tensioner is similar.
4 V-8 engine tensioner.
Loosen
fasteners(A) to relieve belt tension
- Remove drive belt.
4 When reinstalling belt, check that it is correctly positioned on
belt pulleys.
With bolts
(B and C) finger tight, pretension adjuster by
turning hex counterclocltwise
(arrow) to stop.
Tighten mounting bolts.
NOTE-
On 8/97 and later tensioner, turn hex on tensioner plate to
align lowerplate mounting bolt.

Downloaded from www.Manualslib.com manuals search engine
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

Downloaded from www.Manualslib.com manuals search engine
Maintenance
- To remove battery corrosion:
Disconnect battery cables. Disconnect negative (-)cable
first.
* Remove battery from trunk
Clean terminal posts and cable clamps with a wire brush.
Clean main chassis ground terminal next to battery.
Corrosion can be washed away with a
baking soda and
water solution that will neutralize acid.
Reinstall battery and reconnect cable clamps, positive
(+)
cable first.
Lightly coat outside of terminals, hold down screws, and
clamps with petroleum jelly, grease, or a commercial
battery terminal corrosion inhibitor.
WARNING
-
Battery acid is extremely dangerous. Take care to keep it
from contacting eyes, skin, or clothing. Wear eye protection.
Extinguish all
smolihg materials and do not work near any
oaen flames.
CAUTION-
Prior to disconnecting the batteg read the battery discon-
nection cautions given in
001 General Cautions and
Warnings.
NOTE-
The original equipment battery in E39 models is mainte-
nance free. The original electrolyte will normally last the
entire service life of the battery under moderate climate con-
ditions.
Battery electrolyte should be maintained at the correct level
just above the battery plates and theirseparators. The correct
level is approximately
5 mm ('14 in.) above the top of battery
plates or to the top of the indicator
marks (if applicable). The
battery plates and the indicator marks can be seen once the
fillercaps are removed.
if theelectrolyte level is low, replenish
it by adding distilled water only.
4 The original equipment BMW battery is equipped with a
built-in hydrometer "magic eye"
(arrow). Battery condition is
determined by the color of the eye:
Green: Adequate charge
* Black: Inadequate charge, recharge
Yellow: Defective battery, replace
Batteries are rated by ampere hours (Ah), the number of
hours a specific current drain can be sustained before com-
plete discharge, or by cold cranking amps (CCA), the number
of amps available to crank the engine in cold weather
condi-

Downloaded from www.Manualslib.com manuals search engine
020-26
Maintenance
NOTE-
The parking brake may lose some of its effectiveness if it is
not used frequently This is due to corrosion build-up on the
parking brake drum. To remove corrosion, apply the parking
brake just until it begins to grip, then pull the lever up one
more stop (click). Drive the car approximately 400 meters
(1,300
ft.) and release the brake. To recheck the adjustment
of the parking brake see
340 Brakes.
Clutch fluid, checking
In cars equipped with manual transmission and clutch, the hy-
draulic clutch and the brake system share the same reservoir
and the same bralte fluid. Clutch fluid level and brake fluid lev-
el are checked at the same time.
NOTE-
* See 340 Brakes for more information.
See
210 Clutch for information on the clutch and the
hydraulic clutch operating system.
Differential oil level, checking
The E39 differential is filled with lifetime oil that ordinarily
does not need to be changed.
BMW recommends using only
a specially formulated synthetic gear oil
(SAF-XO) that is
available through an authorized
BM\N dealer parts depart-
ment. For additional information on this lubricant and any
other lubricants that may be compatible, contact an
authorized
BMW dealer service department.
< Check rear differential oil level at filler plug (arrow).
- Check lubricant level with car on a level surface:
Level is correct when fluid just reaches edge of filler hole.
If necessary, top up fluid.
Replace filler plug sealing ring.
Install and tighten oil filler plug when oil level is correct.
NOTE-
Use either a 14 mm or 17 mm Allen socket to remove the
drain plug.
If the car is raised in the air, it should be level when
checking or filling final drive fluid level.
Tightening torque
Filler plug to final drive housing 70 Nrn (52 it-lb)

Downloaded from www.Manualslib.com manuals search engine
.-. -
Maintenance
Drive axle joint
(CV joint) boots, inspecting
CVjoint protective boots must be closely inspected forcracks
and any other damage that will allow contaminants to get into
the joint.
If the rubber boots fail, the water and dirt that enter
the joint will quickly damage it.
NOTE-
Replacement of the CVjoint boots and inspection of the
joints are described
in 331 Final Drive.
Exhaust system, inspecting
Exhaust system life varies widely according to driving habits
and environmental conditions. If short-distance driving pre-
dominates, the moisture and condensation in the system will
not fully dry out. This will lead to early corrosion damage and
more frequent replacement.
Scheduled maintenance of the exhaust system is limited to
inspection:
* Check to see that all the hangers (arrow) are in place and
properly supporting the system and that the system does
not strike the body.
Check for restrictions due to dents or
kinlts,
Check for weakness or perforation due to rust.
NOTE-
Alignment of the system and the location of the hangers are
described in
180 Exhaust System.
Fuel filter, replacing
The fuel filter is located beneath the center of the car, approx-
imately under the driver's seat.
A protective cover must be
removed to access the filter.
4 Fuel filter for M62 engine (arrow)
- Disconnect battery negative (-) cable
CAUTIOI\C
Disconnecting the battery cables may erase fault codes
stored
in engine control module memory.
WARNING -
Fuel will be expelled forcibly when the filter is removed. Do
notsmoke or work near heaters orother fire hazards. Keep a
fire extinguisher handy

Downloaded from www.Manualslib.com manuals search engine
020-28
1 Maintenance
- When replacing fuel filter:
Use appropriate hose clamping device to clamp off filter
inlet and outlet hoses to lessen fuel spillage.
Loosen center clamping bracket and hose clamps on
either end of filter.
Note arrow or markings indicating direction of flow on
new filter.
Install new filter using new hose clamps
- Drain fuel filter from inlet side into a container and inspect
drained fuel.
Checlc for rust, moisture and contamination.
I - I < If fuel filter is equipped with fuel pressure regulator:
I 2 / Remove vacuum hose (1)
Pull out locking clip (2).
- Remove fuel pressure regulator (3).
Install pressure regulator in new filter.
Clean thoroughly around the filler connections before
removing them.
After assembly, check filter connections carefully for
I
I lealcs before installing cover.
NOTE- ~-
Additional informarion about the fuel filler assembly is in 160
Fuel Tank and Fuel Pump.
Fuel tank and fuel lines, inspecting
lnspectthe fuel tank, fuel lines, and fuel system fordamage or
lealts. Checlc for fuel lealts in the engine compartment or fuel
odors in the passenger compartment. Check for any evapora-
tive emissions hoses that may have become disconnected,
checking carefully at charcoal canister and evaporative emis-
sions purge system. See
130 Fuel Injection and 160 Fuel
Tankand Fuel Pump for component locations and additional
information.
WARNING-
When checlcing for fuel leal(s, the engine must be cold. A hot
exhaust manifold or exhaust system could cause the fuel to
ignite or explode causing serious personal injury Ventilate
the work area and clean up spilled fuel immediately.

Downloaded from www.Manualslib.com manuals search engine
Maintenance
Suspension, front, inspecting
Inspection of the front suspension and steering includes a
check of all moving parts
forwear and excessive play. Inspect
ball joint and tie-rod rubber seals and boots for cracks
ortears
that could allow the entry of dirt, water, and other
contaminants. See
310 Front Suspension.
Suspension, rear, inspecting
Differential and rear drive axle service consists of checking
and changing the gear oil, inspecting for leaks, and checking
the drive axle
CV joint boots for damage.
The areas where
lealts are most likely to occurare around the
drive shaft and drive axle mounting flanges. For more infor-
mation on identifying oil leaks and theircauses, see
330 Rear
Suspension and
331 Final Drive.
Tires, checking inflation pressure
Correct tire pressures are important to handling and stability,
fuel economy, and tire wear. Tire pressures change with tem-
perature. Pressures should be
checked oRen during season-
al temperature changes. Correct inflation pressures can be
found on the driver's door pillar and in the owner's manual.
Note that tire pressures should be higher when the car is
more heavily loaded.
WARNING-
Do not inflate any tire to a pressure higher than the tire's max-
imum inflation pressure listedon the sidewall. Use care when
adding air to warm tires. Warm tire pressures can increase as
much as
4 psi (0.3 bar) over their coldpressures.
Tires, rotating
BMW does not recommend tire rotation. Due to the car's sus-
pension design, the front tires begin to wear first at the outer
shoulder and the reartires begin to wearfirst at the middle of
the tread or inner shoulder. Rotating the tires may adversely
affect road handling and tire grip.
Transmission service, automatic
The automatic transmissions installed in E39 models are
filled with special automatic transmission fluid. The transmis-
sion lubricant type can be found on the "type-plate" on the
side of the transmission. The recommended lubricants are
listed earlier in this repair group. See Fluids and lubricants.
If in doubt, consult an authorized BMW dealer for alternate