1993 BMW 325i Workshop Manual

5
.
Slowly
add
coolant
until
it
spills
from
bleed
screws
.

When
coolant
spillíng
from
bleed
screws
is
free
of
air

bubbies,
tighten
screws
.

6
.
Run
engine
until
it
reaches
operatíng
temperature
.
Af-

ter
engine
has
cooled,
recheck
coolant
level
and
top
up
as
necessary
.

CAUTION-

Always
use
genuine
BMW
coolant
or
its
equiva-

lent
to
avoid
the
formation
of
harmful,
clogging
de-

posits
in
the
cooling
system
.
Use
of
other
antifreeze
solutions
may
be
harmful
to
the
cooling
system
.

Tightening
Torque

"
Radiator
bleed
screw

to
thermostat
housing
...
.
.
........
8
Nm
(71
in-lb)

Belt-driven
cooling
fan,
replacing

1
.
Usinga32
mm
wrench
on
fan
clutch
nut,
turn
wrench

quickly
in
a
clockwise
direction
(working
from
front
of

car)
to
loosen
.
Spin
fan
off
pump
.
See
Fig
.
8
.

NOTE-

"
The
radiator
cooling
fan
nut(32
mm
wrench)
has
left-
hand
threads
.

"
The
nut
may
be
difficult
to
loosen
.
Use
a
tool
to
hold
the
coolant
pump
pulleystationary
.
BMW
hasa
spe-
cial
tool
forthis
purpose
(BMW
special
tool
no
.
115
030)
.

2
.
Remove
expansion
rivets
holding
shroud
to
radiator
.

See
Fig
.
9
.
Remove
fan
and
shroud
together
.

NOTE-

Store
the
removed
fan
clutch
assembly
in
an
upright
(installed)
positionto
prevent
lossof
clutch
fluid
.

RADIATOR
AND
COOLING
SYSTEM



170-
7

Fig
.
8
.



Radiatorcooling
fannut
(arrow)
.
Nuthas
left-hand
threads
.

3
.
To
replace
fan
clutch,
remove
fan
mounting
bolts
and

separate
clutch
from
fan
.
Fig
.
9
.



Fan
shroud
retaining
rivet
(arrow)
.
Pryout
center
pin
and
re

4
.
Installation
is
reverse
of
rernoval
.



move
rivet
.
Rivet
design
may
vary
depending
on
model
and

model
year
.

Tightening
Torques

"
Clutchnut
to
coolant
pump
(left-hand
threads)

Wíthout
BMW
tool
no
.
11
5
040
.....
40
Nm
(29
ft-lb)

With
BMW
tool
no
.
11
5
040
.
......
30
Nm
(22
ft-Ib)

"
Fan
to
viscous
clutch
...
.
..
.
......
10
Nm
(89
in-lb)

0013203

COOLING
SYSTEM
SERVICE

170-8



RADIATOR
AND
COOLING
SYSTEM

Electric
cooling
fan,
replacing

On
late
4-cylinder
models
(M44
engine)
with
manual
trans-
mission,
the
primary
cooling
fan
is
electrically
operated
and
is
mounted
on
the
engine
side
of
the
radiator
.

1
.
If
necessary,
remove
cover
from
top
of
radiator
.
See
Fig
.
10
.

0012505
Fig
.
10
.
Air
cover
in
back
of
radiator
.
Unclip
cover
from
fan
shroud
af-
ter
removing
mounting
screws
.

2
.
Disconnect
fan
harness
connector
at
bottom
left
of
ra-
diator
.

3
.
Remove
fan
shroud
mountingscrews
at
left
and
right
side
of
radiator
.
Lift
fan
assembly
straight
up
and
offra-
diator
.

4
.
Installation
is
reverse
of
removal
.
Be
sure
to
align
side
tabs
on
fan
housíng
with
retaining
tabs
on
radiator
when
reinstalling
fan
.

Auxiliary
cooling
fan,
replacing

The
auxiliary
electric
cooling
fan
is
mounted
behind
the
front
bumper,
in
front
of
the
A/C
condenser
.
There
aretwo
ver-
sions
of
auxiliary
fans
installed,
depending
on
model
and
en-
gine
installed
.

TType
1
(u
p
to
9192)

1
.
Remove
front
radiator
air
shroud
.
See
Fig
.
11
.

2
.
Remove
fan
mountingscrews
.
See
Fig
.
12
.

3
.
Tilt
fan
forward
.
Disconnect
electrical
harness
connec-
tor
before
lifting
fan
up
.

COOLING
SYSTEM
SERVICE

Fig
.
11
.
Front
radiator
air
shroud
fasteners
(arrows)
.

Fig
.
12
.
Version
1
auxiliary
fan
mountingscrews
(arrows)
.

NOTE
-

If
necessary,
remove
front
bumper
or
lowerengine
cov-
erto
access
electrical
harnessconnector
.

4
.
Installation
is
reverse
of
removal
.

l)
Type
2
(from
9192)
2
.
Remove
fan
mounting
screws
.
See
Fig
.
13
.

0013137

1.
Remove
front
bumper
and
radiator
grilles
.
See
510
Ex-
terior
Trim,
Bumpers
.

3
.
Angle
fan
up
and
forward,
disconnecting
electrical
har-
nessconnectorbehind
it
.
Remove
it
through
bumper
opening
.

Fig
.
13
.
Version
2
auxiliary
fan
mounting
screws
(arrows)
.
Front
bumper
hasbeen
removed
.

4
.
Installation
is
reverse
of
removal
.

Thermostat,
replacing

0013146

The
coolant
thermostat
is
instalied
in
a
housing
at
the
front

of
the
cylinder
head
.
See
Fig
.
14
.

Fig
.
14
.
Coolantthermostat
and
housíng
.

NOTE-

On
M44
engines,
the
thermostat
is
integrated
into
the
thermostat
housíng
.
If
the
thermostat
requiresreplace-
ment,
the
complete
thermostathousing
mustbe
replaced
.

RADIATOR
AND
COOLING
SYSTEM



170-
9

WARNING
-

Allow
the
cooling
system
to
cool
before
opening
ordraining
the
system
.

2
.
Remove
belt-driven
cooling
fan
and
fan
shroudas
de-

scribed
earlier
.

3
.
On
M52/S52US
engines
:
Unclip
wiring
duct
retaining
clips
and
remove
duct
from
above
thermostat
housing
.

Also
remove
engine
front
lifting
bracket
.

4
.
Remove
thermostat
housing
from
front
of
engine
.
See
Fig
.
15
.

Fig
.
15
.
Thermostat
housíng
shown
removed
(6-cylinder
engine)
.

NOTE-

Some
thermostats
have
a
direction
arrowor
venthole
near
the
edge
.
Install
the
thermostat
so
that
either
the
arrow
or
hole
are
at
thetop
.

CAUTION
-

Be
sure
to
reconnect
ground
wire(s)
at
thermostat
housing
mounting
bolt,
where
applicable
.

5
.
Remove
thermostat
.
Note
thermostat
direction
and
ori-

entation
before
removing
.

6
.
Insta¡¡
new
thermostat
and/or
thermostat
housing
using

new
O-ring
and
gasket(s)
as
necessary
.

oo131ss



7
.
Installation
is
reverseof
removal
.
Fill
system
with
cool-

ant
as
described
under
Coolant,draining
and
filling
.

Tightening
Torques

1
.
Drain
radiator
as
described
above
under
Coolant,



"
Thermostat
housing
cover

draining
and
filling
.



to
housing
orcoolant
pump
..
..
....
10
Nm
(89
in-lb)

"
Engine
lifting
bracket
bolt
to
thermostat
housing

(M52/S52US
engine)(M8)
....
..
...
22
Nm
(17
ft-Ib)

COOLING
SYSTEM
SERVICE

170-10



RADIATOR
AND
COOLING
SYSTEM

Coolant
pump,
replacing

The
engine
coolant
pump
is
mounted
in
the
frontof
the
en-

gine
on
the
timing
cover
.
See
Fig
.
16
.

Fig
.
16
.
Coolant
pump
mounted
on
timing
cover
.

NOTE-

Onlyreplacement
coolant
pumps
with
metal
¡mpellers
should
be
installed
.
Pumps
with
plastic
impellers
should
not
be
used
.

1.
Drain
cooling
system
as
described
earlier
.

0013197

WARNING
-

Allow
cool¡ng
system
to
cool
before
open¡ngor
drain¡ng
system
.

2
.
Remove
primary
cooling
fan
shroud
and
cooling
fan
(belt-driven
or
electric)
as
described
earlier
.

Fig
.
17
.
Engine
drive
belt
tensioner
being
released
on
M44
engine
.
Pry
off
tensioner
cover
and
then
lever
tensioner
in
counterciock-
wise
direction
(as
facing
engine)
and
slip
belt
off
pulleys
.

Fig
.
18
.
Drive
belt
tensioner
being
released
on
M52
engine
.
Pry
off
3
.
Disconnect
hoses
from
thermostat
housing
.
Unbolt



tensioner
cover
and
then
lever
tensioner
clockwise
(as
facing
thermostat
housing
from
front
of
cylinder
head
.



engine)torelease
belt
tension
.

4
.
Remove
coolant
pump
drive
belt
.
See
Fig
.
17
or
Fig
.
18
.

NOTE-

-
Mark
direction
of
drive
belt
rotation
if
reusing
belt
.



"
The
6-cylinder
coolant
pump
¡s
mounted
on
studs
and
retained
by
nuts
.
"
Severa¡
drive
belt
and
tensioner
configurations
havebeenused
in
E36
models
.
Refer
to
020
Maintenance
Program
and
640
Heating
and
Air
Conditioning
.

5
.
Remove
coolant
pump
pulley
from
pump
.

6
.
Remove
mounting
fasteners
from
pump
.

COOLING
SYSTEM
SERVICE

NOTE-

"
The
4-cylinder
coolant
pump
¡s
mounted
us¡ng
two
dif-
terent
length
bolts
.
Note
where
thelonger
bolt
fits
dur-
ing
disassembly
.

0011989

7
.
Insert
twoscrews
(M6)
in
tapped
bores
and
tighten
uni-
formly
until
pump
is
free
from
timing
chain
cover
.
See
Fig
.
19
.

Fig
.
19
.
Coolant
pump
being
removed
.
Thread
two
M6
bolts
(arrows)
in
evenly
to
withdraw
pump
.
(Thermostat
and
hoseshavebeen
removed
tor
visual
access
.)

8
.
Installation
is
reverse
of
removal
.

"
Be
sure
to
replace
O-ring
and
gaskets
.

"
Coat
O-ring
with
lubricant
during
installation
.

Tightening
Torque

"
Coolant
pump
to
timing
chaincover

M6
...
.
...................
..
.
.
10
Nm
(89
in-lb)

M8
.
..
.
....................
.
.
.
22
Nm
(17
ft-Ib)

"
Coolant
pump
pulley

to
coolant
pump
.................
10
Nm
(89
in-lb)

RADIATOR
SERVICE

Radiator,
removing
and
installing

1
.
Drain
radiator
as
described
earlier
.

WARNING
-

Allow
cooling
system
to
cool
before
opening
ordraining
system
.

2
.
Remove
primary
cooling
fan
(belt-driven
or
electric)
as

described
earlier
.

3
.
Disconnect
coolingfan
and
leve¡
sensor
harness
con-

nectors
from
bottom
of
radiator,
where
applicable

4
.
Disconnect
harness
connector
from
auxiliary
fandual

temperature
switch
.
See
Fig
.
20
.

5
.
Disconnect
all
coolant
hoses
from
radiator
.

RADIATOR
AND
COOLING
SYSTEM



170-11

0012500

Fig
.
20
.
Cooling
fan
dual
temperatura
switch
(arrow)
on
right
sido
of
radiator
.

6
.
Where
applicable,
disconnectautomatic
transmission
fluid
(ATF)
cooler
lines
from
radiator
.
See
Fig
.
21
.

Fig
.
21
.
Automatic
transmission
fluid
(ATF)
linos
at
radiator
.

7
.
Carefully
pryout
radiator
retaining
clips
from
top
of
ra-

diator
.
See
Fig
.
22
.

8
.
Pul¡
radiator
up
and
out
of
car
.

NOTE-

The
radiator
rests
ontwo
rubber
mounts
.
Check
that

the
mounts
do
not
stick
to
the
bottomof
the
radiator
.

RADIATOR
SERVICE

170-12



RADIATOR
AND
COOLING
SYSTEM

Fig
.
22
.
Radiator
retaining
clip
being
removed
.
Push
down
and
pulí
screwdriver
forward
to
release
clip
.

9
.
Installation
is
reverse
of
removal
.

"
Fill
radiator
and
cooling
system
as
described
under
Coolant,
draining
and
filling
.
"
Check
ATF
leve¡
and,
if
necessary,
top
up
.
See
240
Au-
tomatic
Transmission
.

RADIATORSERVICE

GENERAL
.
.
.......
.
......
.
...
.
.
.
.
.
...
180-1



Exhaust
system,
removing
and
installing
.
...
.180-3

EXHAUST
SYSTEM
REPLACEMENT
.
...
180-1



Exhaust
manifolds,
removing
and
installing
.
.
.180-5

GENERAL

The
exhaust
system
is
designed
to
be
maintenance
free,
al-
though
regular
inspection
is
warranted
due
to
the
harsh
oper-
atingconditions
.
Under
normal
conditions,
the
catalytic

converter
does
not
require
replacement
unless
it
is
damaged
.

On
1996
and
later
cars,
a
pre-
and
post-catalytic
converter

oxygen
sensor
is
used
at
each
catalytic
converter
.
Be
sure
to

take
care
when
removingthe
system
not
to
damage
the
sen-



EXHAUST
SYSTEMREPLACEMENT
sors
.

See
130
Fuel
Injection
for
information
on
testing
oxygen

sensors
.

NOTE-

OnM52
engines,
two
resonator
pípes
(short
and
long)
are
incorporated
into
the
rear
muffler
assembly
.
See
Fíg
.
1
.
An
exhaust
flap
is
integrated
into
the
outlet
side
of
the
short
pipe
.
The
flap
is
operated
by
a
vacuum
ac-
tuator
via
the
Siemens
MS
41
.1
engine
control
mod-
ule)
.
The
flap
is
closed
at
engine
speeds
below
2,500
rpm
.
This
allows
exhaust
gasses
to
flow
through
the
long
resonator
pipe
and
reduce
noise
.
Above
2,500rpm,
the
exhaust
flap
is
open
(no
vacuum
applied
to
the
actuator)
and
allows
exhaust
gasses
to
flow
through
the
short
pipe
for
maximum
performance
.

180
Exhaust
System

0013101

Fig
.
1
.



Rear
muffler
(active
silencer
usedon
M52
engines)
.
Vacuum

operated
flap
(A)
changesbetween
short
and
long
pipes,
de-

pending
on
engine
speed
.

EXHAUST
SYSTEM



180-1

WARNING
-

Exhaust
gases
are
colorless,
odorless,
and
very
toxic
.
Run
the
engine
only
ín
a
well-ventilated
area
.
Immediately
repair
any
leaks
in
the
exhaust
system
or
structural
damage
to
the
car
body
that
might
al-
lowexhaust
gases
to
enter
the
passenger
compart-
ment
.

Exhaustsystem
components
are
detailed
in
Fig
.
2
through

Fig
.
4
.

New
fasteners,
clamps,rubber
mounts,
and
gaskets
should

be
used
when
replacing
exhaust
components
.
A
liberal
appli-
cationof
penetrating
oil
to
the
exhaustsystem
nuts
and
bolts
in
advance
may
make
removal
easier
.

WARNING
-

"
The
exhaust
system
and
catalytic
converter
op-
erate
at
high
temperatures
.
Allow
components
to
cool
before
servicing
.
Wear
protectíve
clothíng
to
prevent
bums
.
Do
not
use
flammable
chemicals
near
a
hot
catalytic
converter
.

"
Old,
corroded
exhaust
system
components
crumble
easíly
and
often
have
exposed
sharp
edges
.
To
avoid
injury,
wear
eye
protection
and
heavy
gloves
when
working
with
old
exhaust
parts
.

EXHAUST
SYSTEM
REPLACEMENT

T

180-2



EXHAUST
SYSTEM

a

EXHAUST
SYSTEM
REPLACEMENT

Fig
.
2
.



Exhaust
systemon
1992-1995
6-cylinder
engines
.
3251
(M50)
exhaust
system
shown
.

E~

)l-,malo
m~=

i

32592-95

1
.



Front
pipe
with
catalytic
convertor



6
.



Bracket



11
.



Bracket/clamp
(2)



16
.



Rear
pipewith
muffler
2
.



Gasket
(2)



7
.



Bracket
(2)



12
.



Rubber
mounting
ring
(2)



17
.



Rubber
mount
3
.



Exhaust
manifold



8
.



Bracket



13
.



Flange



18
.



Support4
.



Exhaust
manifold



9
.



Bracket



14
.



Gasket
(48mm)



19
.



Bracket
5
.
Manifold
gasket



10
.
Oxygen
sensor



15
.
Gasket
(48mm)

eme°"



k
:I>
-
8a

1
.



Exhaust
manifold



7
.



Front
pipe
with
catalytic
con-



9
.



Bolt
(M8X90)



14
.



Brackets
(rear
muffier)
2
.



Nut
(M10)



vertor



10
.



Compression
spring



15
.



Rear
muffler
and
pipe
3
.
Gasket
(clty
.
2)



8
.



Oxygen
sensor
(regulating)



11
.



Self-lockingnut
(M8



16
.



Bracket
(transmission)
4
.
Gasket



-tightento
55
Nm
(41
ft-Ib)



-always
replace



17
.



Brackets
(transmission)
5
.



Nut



8a
.



Oxygen
sensor
(monitoring)



12
.



Bracket
(rear
pipe)
6
.



Bolt
(M8X55)



-tightento
55
Nm
(41
ft-Ib)



13
.



Rubber
mounting
ring
(9ty
2)

Fig
.
3
.



Exhaust
systemon
1996-1998
4-cylinder
(M44)
engine
.1992-1995
4-cylinder
engine
exhaust
system
is
similar
.