1997 BMW 328i heater core flange

640-4



HEATING
AND
AIR
CONDITIONING

Heater
box,
removing
and
installing

The
heater
box,
located
underneath
thecenter
of
the
dash-

board,
houses
theheater
core,
the
A/C
evaporator,
and
asso-

ciated
sensors
and
actuators
.
Removal
of
theheater
box

requires
that
the
A/C
refrigerant
be
discharged
.

CAUTION-

"
Removing
the
heater
box
requires
evacuating
the
AIC
system
.
DO
NOT
attempt
this
procedure
without
proper
tools
and
training
.

"
Any
person
who
services
a
motor
vehicle
air
con-

ditioner
must,
by
law,
be
properly
trained
and
cer-
tified,
and
use
approved
refrigerant
recycling
equipment
.
Technicians
must
complete
an
EPA-
approved
recycling
course
to
be
certified
UU12639

Fig
.
10
.
Heater
core
mounting
nuts
at
left
sideof
bulkhead
(arrow)
.

1
.
Drain
engine
coolant
.
See
170
Radiator
and
Cooling



wiper
assembly
shown
removed
for
clarity
.

System
.

2
.
Remove
complete
dashboard
.
See513
Interior
Trim
.

3
.
Remove
blower
motoras
described
earlier
.

4
.
Remove
nut
retaining
water
hose
flange
to
rear
bulk-
head
.
I'ush
flange
to
one
side
.
See
Fig
.
9
.

Fig
.
9
.



Nut
retaining
coolant
hose
flangeat
bulkhead
(arrow)
.

NOTE-

Clear
any
remaining
coolant
from
the
heater
core
by
blowing
compressed
air
finto
the
coolant
feed
hose
.

HEATER
AND
CONTROLS

0012638b

6
.
Cut
wire
tie
holding
wire
harness
to
heater
box
and
dis-

connect
cable
harness
connector
from
heater
box
.
See

Fig
.
11
.

0012647

Fig
.
11
.
Harness
connectors
(A)
and
cable
tie
(B)
at
heaterbox,
under
driver
side
dash
.

7
.
Followingmanufacturer's
instructions,
connect
ap-

proved
refrigerant
recovery/recycling/recharging
unitto

A/C
system
and
discharge
system
.

8
.
Unbolt
A/C
refrigerantlines
flange
from
engine
bay
bulkhead
.
See
Fig
.
12
.

9
.
On
models
with
rotary-knob
A/C
control
head
:
Discon-
5
.
Remove
nuts
from
heater
box
retaining
bracket
on
en-



nect
wiring
harness
connectors
to
A/C
control
module
gine
bulkhead
left
side
.
See
Fig
.
10
.
Repeat
procedure



in
center
console
and
remove
module
.
See
Fig
.
13
.
for
right
side
nuts
.

640-6



HEATING
AND
AIRCONDITIONING

Heater
core,replacing

1.
Drain
engíne
coolant
.
See170
Radiator
and
Cooling

System
.

WARNING
-

Allow
the
cooling
system
to
cool
before
opening
or
drainíng
the
cooling
system
.

2
.
Remove
center
console
.
See
513
Interior
Trim
.

3
.
Remove
Multi-Information
Display
(MID)
module
.
See

620
Instruments
.

4
.
Remove
lower
dash
panel
and
knee
bolster
on
driver

side
.
See
513
Interior
Trim
.

Fig
.
17
.
Wire
harness
retaining
clips
and
wire
ties
at
heater
box
cover
5
.
Working
under
driver
side
of
dash,
remove
coolant



(arrows)
.
flange
from
heater
core
.
See
Fig
.
16
.

0012651

Fig
.
16
.
Bolts
at
3-way
coolant
flange
under
driver's
side
of
dash
(ar-
rows)
.

NOTE-

Residual
coolant
in
heater
core
will
spill
.
Protect
thecarpet
.

6
.
Working
at
front
of
driveshaft
tunnel,
unclip
wire
har-

nesses
and
move
to
one
side
in
front
of
heater
box
.
See
Fig
.
17
.

7
.
Remove
heatercore
temperature
sensorsas
described

later
in
this
repair
group
.

8
.
Remove
front
heater
box
cover
.
See
Fig
.
18
.

9
.
On
right
side
of
heater
box,
unclip
heater
air
duct
actu-
ating
lever
.
Remove
cross-rod
(with
flaps)
from
frontof
heater
core
.
See
Fig
.
19
.

HEATER
AND
CONTROLS

0012662

Fig
.
18
.
Screws
retaining
front
heater
box
cover
(shown
removed)
to
heater
box
(arrows)
.

0012661
Fig
.
19
.
Pry
heater
flap
actuating
lever
in
direction
A
.
Pull
offair
flap
cross-rod
in
direction
B
.

10
.
Pul¡
heater
core
up
and
backward,
away
from
heater
box
.
If
necessary,
remove
left
and
right
reinforcing
bracket
bolts
.
See
Fig
.
20
.

CAUTION-

Replace
coolant
flange
O-rings
and
tighten
fas-
teners
to
specified
torques
.

Tightening
Torques

1
.
Remove
center
console
.
See
513
Interior
trim
.

0012660

Fig
.
20
.
PA
heater
core
upand
towardback
of
car
.
Lower
mounting
bolts
for
steering
column
brace
and
glove
compartment
sup-
port
frame
may
have
to
be
removed
(arrows)
.

11
.
Installation
is
reverse
of
removal
.
Fill
and
bleed
cooling

system
.
See
170
Radiator
and
Cooling
System
.

"
Coolant
flange
to
heater
core
.
..
....
3
Nm
(27
in-lb)



Heater
andA/C
Control
Head

Heatercore
temperature
sensor,
replacing

The
automatic
heating
and
air
conditioning
systemuses

severa¡
sensors
to
control
interior
air
temperature
.
Use
the
fol-

lowing
procedure
and
the
data
in
Table
b
to
pinpoint
problems

with
theheater
core
sensors
.

2
.
Remove
Multi-Information
Display
(MID)
module
.
See

6201nstruments
.

HEATING
AND
AIR
CONDITIONING



640-7

0012648

Fig
.
21
.
Remove
heatercore
temperaturesensors
in
direction
shown
(arrow)
.

Table
b
.
Heater
CoreTemperatureSensor
Test

Values

Test
temperature



Resistance

4°F
(-20°C)



84
.39
-
109
.61
k
ohms

14
°
F
(-10°C)



48
.58
-
62
.09
k
ohms

32°F
(0°C)



28
.89
-
36
.40
k
ohms

68°F
(20°C)



11
.13
-
13
.83
k
ohms

140°F
(60°C)



2
.19
-
2
.78
k
ohms

212°F
(100°C)



0
.58
-
0
.77
k
ohms

Two
types
of
heater
and
aír
conditioning
control
heads
viere
installed
in
E36
cars
.
Early
models
have
control
heads
with
four
rotary
knobs
and
a
separate
control
module
.
A
flexible

shaft,
clipped
to
the
right
sideof
the
control
head,
controls
the
heater
flaps
.

Later
model
E36
cars,
starting
in
approximately
mid-1995,

have
digital
display
control
heads
with
buttons
.
The
A/C
con-
trol
module
is
integrated
with
the
digital
control
head
.

Heater
and
A/C
control
head,

removing
and
installing
(rotary-knob)

3
.
Pul¡
temperature
sensors
from
heater
box
and
discon-



1
.
Remove
Multi-Information
Display
(MID)
module
from

nect
harness
connectors
.
See
Fig
.
21
.



center
of
dash
.
See
620
Instruments
.

4
.
Installation
is
reverse
of
removal
.



2
.
Pul¡
off
outer
rotary
knobs
from
A/C
control
head
.
Re-

move
two
screwsonknob
bezels
.
Remove
control
pan-

el
face
plate
by
prying
it
off
control
head
gently
.
See
Fig
.

22
.

3
.
Carefully
push
control
head
back
into
dash
and
down-

ward
through
MID
opening
.
See
Fig
.
23
.

HEATER
AND
CONTROLS