1997 BMW 525i ECO

Downloaded from www.Manualslib.com manuals search engine
General
Table a. General bolt tightening torques in Nm
(max. permissible)
Bolt Class (according to DIN
267)
Gaskets and seals
Gasket aredesigned to crush and become thinner as the mat-
ing parts are bolted together. Once agasket has been used, it
is no longer capable
;f malting as good a seal as when new,
and is much more likely to leak.
Forthis reason, gaskets
should not be reused.
Some gaskets and seals are
d~rectional. Make sure thatthese
are
~nstalled correctly. In places where a shaft must pass
through a housing,
flex~ble lip seals are used to keep the lubri-
cating
011 or grease from leaking out past the rotatlng shaft.
Seals should never be reused once they have been removed.
When
rernovlng a seal, be careful not to damage the metal
surfaces.
The ltey to seal installation is to get the seal in straight without
damaging it. Use a seal driver that is the same diameter as
the seal housing to gently and evenly install into place.
If a
proper size seal driver is not available, a socket of the right
size will do.
Some seals are directional and special installation instruc-
tions apply. Make sure a seal is installed with the lip facing the
correct way. Note the installation direction of the old seal be-
fore removing it.

Downloaded from www.Manualslib.com manuals search engine
01 0-1 0
General
Electrical testing
Many electrical problems can be understood and solved with
only a little fundamental knowledge of how electrical circuits
function.
Electrical current
only flows in a complete circuit. To operate.
every electrical device in the car requires a complete circuit
including a voltage source and a path to ground. The positive
(+) side of the battery is the original voltage source, and
ground is any return path to the negative
(-) side of the bat-
tery, whether through the wiring harness or the car body. Ex-
cept for portions of the charging system, all electrical current
in the car is direct current (DC) and flows from positive
(+) to
negative
(-).
4 Switches are used to turn components on or off by complet-
ing or interrupting the circuit.
A switch is "open" when the cir-
cuit is interrupted, and "closed" when the circuit is completed.
See
600 Electrical System-General for electrical trouble-
(LW, 1 shooting
Wire repairs
Light bulb
(consumer) ' - Repairs to a wiring harness require special care to make the
repair permanent. The wire ends must be clean.
if frayed or
Car body otherwise damaged, cut off the end and remove enough insu- (ground) i Battery lation to complete the repair. if the wire is too short, splice in a BOZLiEL new piece of wire of the same size and make two connec-
tions.
Use connectors that are designed for the purpose. Crimped
on orsoldered-on connectors are best. Crimp connectors and
special crimping pliers are widely available. If soldering, use
needle nose pliers to hold the wire near the solder joint and
create a "heat dam". This keeps the heat and the solder from
traveling up the wire. Always use a solder made specifically
for electrical
work (rosin core).
NOJE-
Twisting wires together to make a repair is not recommend-
ed. Corrosion and vibration will eventually spoil the connec-
tion and may lead to irreparable damage to sensitive
electronic components.
Insulate the finished connection. Electronics stores can sup-
ply heat-shrinkable insulating tubing that can be placed on to
the wire before connecting, slid over the finished joint, and
shrunic to a tight fit with a heat gun or hair dryer. The next best
alternative is electrical tape. Make sure the wire is clean and
free of
solder flux or other contamination. Wrap the joint tight-
ly to seal out moisture. See
600 Electrical System-General
for more information.

Downloaded from www.Manualslib.com manuals search engine
- - ..
General
Many of the maintenance and repair tasks in this manual call
forthe installation of new parts, orthe use of new gaskets and
other materials when reinstalling parts. Most often, the parts
that will be needed should be on hand before beginning the
job. Read the introductorytext and the complete procedure
to
determine which parts will be needed.
NOTE-
For some biggerjobs, partial disassembly and inspection is
required to determine a complete parts list. Read the proce-
dure carefully and, if necessary, male other arrangements to
get the necessary parts while your car is disassembled.
Genuine BMW parts
Genuine BMW replacement parts from an authorized BMW
dealer are designed and manufactured to the same high stan-
dards as the original parts. They will be the correct material.
manufactured to same specifications, and guaranteed to fit
and work as intended. Most genuine BMW parts carry a limit-
ed warranty.
Many independent repair shops make a point of using genu-
ine
BMW parts, even though they may at times be more ex-
pensive than parts from other sources. They know the value
of doing the job right with ihe right parts. Parts from other
sources can be as good as BMW parts, particularly if manu-
factured by one of
BMW's or~ginal equipment suppliers, but it
is often difficult to know.
BMW is constantly updating and improving their cars, often
malting improvements during a given model year. BMW may
recommend a newer, improved part as a replacement, and
your authorized dealer's parts department will know about it
and provide it. The BMW parts organization is best equipped
to deal with your BMW parts needs.
Non returnable parts
Some parts cannot be returned, even for credit. The best ex-
ample is electrical parts, which are almost universally consid-
ered non returnable. Buy electrical parts carefully, and be as
sure as possible that a replacement is needed, especially for
expensive parts such as electronic control units. It may be
wise to let an authorized BMW dealer or other qualified shop
confirm your diagnosis before replacing an expensive non re-
turnable
Dart.

Downloaded from www.Manualslib.com manuals search engine
BMW dealers are uniquely qualified to provide service for
BMW cars. Their authorized relationship with the large BMW
service organization means that they have access to special
tools and equipment, together with the latest and most accu-
rate repair information.
The BMW dealer's service technicians are highly trained and
very capable. Authorized BMW dealers are committed to sup-
porting the BMW product. On the other hand, there are many
independent shops that provide quality repairwork.
Checking
with other BMW owners for recommendations on service fa-
cilities is good way to learn of reputable BMW shops in your
area.
Most maintenance can be accomplished with a small selec-
tion of tools. Tools range in quality from inexpensive junk,
which may break at first use, to very expensive and
well-
made tools for the professional. The best tools for most do-it-
yourself BMW owners lie somewhere in between.
Many reputable tool manufacturers offer good quality, moder-
ately priced tools with a lifetime guarantee. These are your
best buy. They cost a little more, but they are good quality
tools that will do what
Is expected of them. Sears' Craftsman@
line is one such source of good quality tools.
Some of the repairs covered in this manual require the use of
special tools, such as a custom puller or specialized electrical
test equipment. These special tools are called out in the text
and can be purchased through an authorized BMW dealer.
As an alternative, some special tools mentioned may be pur-
chased from the following tool manufacturers and/or distribu-
tors:
Specialty tool suppliers
Assenmacher Specialty Tools
6440 Odeli Place
Boulder. CO 80301
Baum Tools Unlimited, Inc.
P.O. Box 5867
Sarasota.
FL 34277-5867

Downloaded from www.Manualslib.com manuals search engine
.-
General
4 An adjustable wrench can be a useful addition to a small tool
kit. It can substitute in a pinch if two wrenches of the same
size are needed to remove a nut and bolt. Use extra care with
adjustable wrenches, as they tend to loosen, slip, and dam-
age fasteners.
Jack stands
v
BOOBFNG
4 Strong jack stands are extremely important for any work that
is done under the car. Use only jack stands that are designed
for the purpose.
Blocks of wood, concrete, bricks, etc. are not
safe or suitable substitutes.
A
jaclc should be used only to raise the vehicle, not to support
the car for a long period. Always use
jack stands to support a
Jackstands are available in several styles. The best ones are
:
made of heavy material for strength, have a wide base for sta-
bility, and are equipped to positively lock in their raised posi-
tion. Get the best ones available.
Compared to
a wrench of the correct size, an adjustable
Oil change equipment
wrench is always second best. They should only be used
when the correct size wrench is not available. Choose one of
average size range, about
6 to 8 inches in length.
4 Changing engine oil requires a 17 mm socket or wrench to
loosen and tighten the drain plug and a drain pan (at least
8
quart capacity). A wide, low drain pan will fit more easily un-
der the car. Use a funnel to pour the new oil into the engine.
BMW engines use an oil filter canister with a disposable filter
cartridge insert. A
36 mm socket or wrench is required to re-
move the oil filtercanistercover. See
020 Maintenance foroil
change instructions.

Downloaded from www.Manualslib.com manuals search engine
.
General
Torque wrench
A torque wrench is used to precisely tighten threaded fasten-
ers to a predetermined value. Many of the repair procedures
in this manual include BMW-specified torque values
in New-
ton-meters (Nm) and the equivalent values in foot-pounds
(ft-
Ib).
4 Several types of torque wrenches are available. An inexpen-
sive beam-type (top) is adequate but must be read visually. A
ratchet-type (bottom) can be preset to indicate (click) when
the torque value has been reached. They all do the same job,
but offer different convenience features at different prices.
The most convenient ones have a built-in ratchet, and can be
preset to indicate when a specific torque value has been
reached. Follow the wrench manufacturer's directions
for use
to achieve the greatest accuracy.
A torque wrench with a range up to about 150 Nm (1 10 ft-lb) BOIBFNG has adequate capacity for most of the repairs covered in this
manual. For recommended torque values of
10 Nm orbelow,
the English system equivalent is given in inch-pounds (in-lb).
These small values may be most easily reached using a
torque wrench calibrated in inch-pounds. To convert
inch-
pounds to foot-pounds, divide by 12.
Digital multimeter
4 Many of the electrical tests in this manual call for the mea-
surement of resistance (ohms) or voltage values. For safe
and accurate tests of sensitive electronic component and
systems, a multimeter or digital
volt/ohm meter (DVOM) with
high input impedance (at least
10,000Sr) should be used.
Some meters have automotive functions such as dwell and
pulse width that are useful for troubleshooting ignition and
fuel injection problems.
CAUTIOI\C
Vehicle electronic systems may be damaged by the high cur-
rent draw of a test light with a normal incandescent bulb. As
a general rule, use a high impedance digital multimeter or an
LED test light for all electrical testing.

Downloaded from www.Manualslib.com manuals search engine
-
General
BMW special tools
Many repairs covered in this manual call for the use of BMW
special tools. Many of the BMW special tools mentioned in
this manual are simply the best thing to use to do the job cor-
rectly. In these cases, the tool is identified with a
BMW parl
number. See your authorized BMW dealer parts department
for information on how to order special tools.
There are some jobs for which expensive special tools are es-
sential, and not a cost-effective purchase for a one time repair
by the do-it-yourself owner. This manual includes such re-
pairs for the benefit of those with the necessary experience
and access to tools. For the do-it-yourselfer, the need for spe-
cial tools is noted in the text, and whether or not BMW dealer
service is recommended.
Changing a tire
- Stop car on as flat a surface as possible, in a place where you
can be easily seen by other drivers. Avoid stopping just over
the crest of a hill.
WARNING -
If a tire goes flat while driving, pull well off the road. Changing
a tire on a busy slreet or liigliway is very dangerous. If
nec-
essag drive a short distance on the flat tire to get to a safe
place. It is much better to ruin a tire or rim than to
risk being
hit.
-
- Turn on emergency flashers, and set out flares or emergency
markers well behind car.
Choclc wheel (wheel chock located
in trunk) diagonally opposite to the one being changed. Pas-
sengers should get out of car and stand well away from road.
- Take jaclc and tools from tool area beneath trunk mat. Re-
move spare tire from tire storage tray.
- Loosen wheel bolts while car is on ground, but leave them a
little snug.
< Place jack in lifting point nearest wheel being changed. Use
a board to provide a firm footing for jack if ground is soft.
Raise car only far enough so that the wheel is fully off ground
and then remove wheel nuts and wheel.
- Install spare wheel. Install wheel nuts and tighten them hand
tight using lug nut wrench.

Downloaded from www.Manualslib.com manuals search engine
General
Cars with discharged or dead batteries can be jump-started
using the good battery from another car. See owner's manual
for proper instruction on jump starting. When jump-starling
the engine, always note the following warnings.
4 Lower car. With all wheels on ground, fully tighten nuts in a
WARNING-
* Battery acid (electrolyte) can cause severe burns, and will
damage the
cal; clothing, and you. If electrolyte is spilled,
wash the surface with large quantities of water.
M itgets into
eyes, flush them with water for several minutes and call a
doctor.
B4
5
43
2 BOOIFNG.
Batteries produce explosive and noxious gasses.
Keeps sparks and flames away. Do not smoke near
batteries.
Do notjump-start the engine
ifyou suspect that the bat-
tery is frozen. Trappedgas may explode. Allow the bat-
tery to thaw first.
Do not quick-charge the battery (for boost starting) for
longer than one minute, and do not exceed
16.5 volts
at the battery with the boosting cables attached. Wait at
least one minute before boosting the battery a second
time.
crisscross pattern.
Torque wheel nuts when installing wheel.
Check inflation pressure of spare tire.
Tightening torque
Wheel to wheel hub 120 Nm (89 ft-ib)
Jump starting
Indicator and warning lights
Many vehicle systems are self-monitored for faults while driv-
ing. Generally,
a red warning lamp that comes on during driv-
ing should be considered serious. If you cannot immediately
determine the seriousness of the warning light, stop the vehi-
cle in a safe place and turn the engine off as soon as possible.
Consult the owner's manual for additional information on the
warning lamp and the recommended action.
If the Malfunction Indicator Lamp (MIL)
(Check Engine or Ser-
vice Engine Soon warning light) comes on orflashes, it indi-
cates that an emissions-related fault has occurred. Faults
such as a bad oxygen sensor or a dead fuel injector can
cause the exhaust or evaporative emissions to exceed a
specified limit. When these limits are exceeded, the MIL will
be turned on. The engine can be safety driven with the light
on, although the emission systems should be
checked as
soon as possible. See OBD On-Board Diagnostics for