Mercedes-Benz 300 SD 1978 User manual

You have chosen to drive a MERCEDES-BEN , a car in whose
construction and production we have taken great pains because we
believe that quality is not a matter of chance.
Perhaps you have already had experience with a MERCEDES, maybe this
is your first car from the DAIMLER-BEN company. In both cases — for
your own benefit — please read this owner’s manual before putting it away.
Even though you have been driving a car for years, some things in this car
may be new to you, and this manual certainly contains a few hints which will
help you to make the most of your new car.
We wish you safe and pleasant motoring.
DAIMLER-BEN Aktiengesellschaft
3

Contents
This Owner’s Manual also describes
optional extras as far as this is
required for their operation.
As the scope of delivery is determined
by the order the equipment of your
vehicle may deviate from the
descriptions and illustrations to some
extent.
The last page
What you should know at the gas
station
Vehicle Operation
Instruments and C on trols 8
Instrument Cluster ......................... 10
Keys, Doors
..................................... 12
Master Key and
Supplementary K e y ................... 12
Opening, Locking and
Unlocking of Doors ..................... 12
Master Lock System ................. 13
Seats ................................................. 14
Front Seat Adjustm ent 14
Safety Headrest ........................... 14
Arm Rest (Rear Seat) ................. 15
Safety Belts
................................. 15
C ontrols ............................................. 17
Steering Lock ............................. 17
Idle Speed A djuster ................... 17
Light S w itch ................................. 18
Combination S w itch ................... 19
Cruise C on trol ............................. 20
Automatic Climate Control .......... 21
Various Equipm ent ......................... 25
Interior Lights ............................. 25
Rear View M irrors ....................... 25
Sun Visor ..................................... 25
Electric Window Lifters ............ 26
Lighter ........................................... 27
Shelf below Rear Window .... 27
Heated Rear W indow .............. 27
Sliding R o of ............................... 27
Radio ............................................... 28
Driving
Hood ................................................. 34
Parking Brake ............................... 34
Regular Inspections .................... 35
Starting and Turning
off the E ngine ................................. 36
Starting and Shifting Gears .... 38
Safe Driving ................................... 40
Brake Pad Wear Indicator ... 42
Brake F luid ................................. 42
Charge Indicator Light 42
Oil Pressure Gauge
................ 42
Coolant Temperature Gauge . 42
Emission C ontrol
...................... 43
Driving Econom ically .................. 43
Fuel Consumption .................. 43
Engine Oil C onsum ption 43
The First 1,000 Miles (1,500 km) 43
Special Operating Conditions .. 44
Winter Driving .......................... 44
High Altitude Correction
Device ......................................... 44
Traveling Abroad .................... 44
4

Contents
Vehicle Care
MERCEDES-BEN Maintenance
System ............................................. 46
Severe Operating Conditions . 46
Engine Oil Change and Filter
Change ....................................... 47
Automatic Transmission —
Fluid and Filter Change 47
Spare Parts S ervice
.................... 47
Cleaning and Care of the Vehicle 48
Jobs related to C are ................ 49
Practical Hints
Ash tra y s ......................................... 52
Rear Seat Cushion
....................... 52
First Aid K it
..................................... 53
Vehicle Tool K it............................. 53
Luggage or Ski Racks ................ 53
Wheels, Tires, Changing Wheels 54
Wheels, T ires ............................. 54
Changing W heels .................... 55
Tire Inflation Pressure 56
Fuel System
.................................. 57
Bleeding the Fuel System .... 57
Checking Fuels, Coolants,
Lubricants, etc ................................ 57
Engine Oil Lvel Check
.......... 57
Checking Coolant Level .... 58
Replenishing C oolant .............. 58
Fluid Level —
Automatic Transm ission 59
Electrical System ........................... 60
Replacing Bulbs ....................... 60
Fuses ........................................... 63
Battery ......................................... 63
Sliding Roof Emergency
Operating
....................................... 64
Unlocking of the Filler F la p 64
Tow-starting and Towing
the Vehicle ..................................... 65
Turning off Engine Manually .... 66
Technical Data, Fuels, Coolants,
Lubricants, etc.
Identification Plates .................. 68
Vehicle Data C ards ....................... 68
Technical D a ta ............................... 69
Fuels, Coolants, Lubricants, etc. 71
Capacities ................................... 71
Engine O ils ................................. 73
Brake F luid
................................. 73
Diesel Fuels ............................... 74
C oolants ..................................... 75
Service Literature ......................... 76
Vehicle Operation
Driving
Vehicle Care
Practical Hints
Technical Data, Fuels,
Coolants, Lubricants, etc.
5

Vehicle Operation

Instru ents and Controls
For more detailed descriptions see quoted pages.
1 Speaker grilles
2 Adjustable louvers for side ventilation (page 21)
3 Control lever for side ventilation (page 21)
4 Parking brake release knob (page 34)
5 Handle to disengage hood lock (page 34)
6 Parking brake pedal (page 34)
7 Combination switch (page 19)
8 Light switch (page 18)
9 Cruise control (page 20)
10 Idle speed adjuster (page 17)
11 Instrument cluster (page 10)
12 Horn control
13 Steering lock (page 17)
Steering lock with preglow/starter switch
14 Adjustable louvers for cooled air (page 21)
15 Switch for rear passenger compartment light
16 Switch for automatic antenna (page 30)
17 Switch for heated rear window (page 27)
18 Switch for electric sliding roof (page 27)
19 Automatic climate control (page 21)
20 Radio (page 28)
21 Ash tray with lighter (page 27, 52)
22 Loudspeaker — fader control (page 29)
23 Switch group for window lifters (page 26)
24 Switch for hazard warning flasher system
Push switch = hazard warning flasher
system switched on
Push switch once more = hazard warning
flasher system switched off
25 Glove compartment (to open, shift handle
sideways). Only illuminated if steering lock is
in position “ 1” or “2”.

Instru ents and Controls
9

Instru ent Cluster
1 Coolant temperature gauge (° F)
Red marking: Maximum permissibletemperaturefor
an antifreeze-blended fill protecting down to -22° F
(-30° C)
2 Fuel gauge with reserve warning light (amber)
Fuel reserve for approx. 30 miles (45— 50 km)
For capacity, refer to page 72 and last page.
3 Oil pressure gauge
4 Main odometer
5 Trip odometer
6 Knob for clock adjustment
(press in for adjustments)
7 Electric clock
8 Tachometer
9 Turn signal indicator light, right (green)
10 Preglowing indicator light (amber)
11 Seat belt warning light (red)
12 Brake pad wear indicator light (red):
Light comes on while braking and driving if the front
wheel brake pads are worn down, refer to page 40
13 Dimmer knob for instrument lighting, continuous
adjustment
14 Reset knob for trip odometer
(push button)
15 Brake warning light (red) comes on if
• the parking brake is engaged
• too little brake fluid is in the reservoir
16 High beam indicator light (blue)
17 Charge indicator light (red):
Comes on when the steering lock key is moved to
driving position “2” and must go out when the engine
is idling
18 Turn signal indicator light, left (green)

Instru ent Cluster
FASTEN
BELTS
<
9039
11

Keys Doors
►
Master Key — square head — fits all
locks on the car.
Supple entary Key — rounded head
— fits only the door locks and the
steering lock. This key is intended to
be used whenever the car is left with
an attendant. Be sure to lock glove
compartment and trunk with the
master key.
Opening the Doors
From outside: pull handle out
wards (1).
From inside: pull handle in door trim
panel.
Locking and Unlocking of Doors
From the outside: turn key.
From the inside: actuate plunger.
2 Unlocking
3 Locking
When the rear door plunger’s are
pushed down the rear doors cannot
be opened from the outside or the
inside. They can be opened after
pulling plungers up.
One cannot lock:
<1 the driver’s door if it is open.
<1 any door if the door lock has not
engaged fully. In this case open the
door and close it again.
12

Keys Doors
Master Lock Syste
The master lock system simultane
ously locks or unlocks together with
the driver’s door all other doors, fuel
tank filler flap and trunk lid. As the
driver’s door plunger is moved, the
plungers of all other doors must move
at the same time. If this is not the
case, the lock of the corresponding
door has not engaged fully. Open the
door once more and close it cor
rectly.
When the master lock system has
been applied, the lock plungers of the
front passenger door and the rear
doors can also be operated manually
from inside. In addition to this, the
front passenger door can be locked or
unlocked by means of the key.
The master lock system can only be
applied by depressing the plunger on
the driver’s door. Lock plungers of the
other doors cannot be depressed
individually.
The trunk lid can also be unlocked
separately by turning master key
clockwise to the stop. Push the trunk
lock button in with it and lift the lid.
Return the key to its initial position
and withdraw it. To lock the lid, close it
firmly. It will then be locked again by
the master lock system.
A provision has been made to
facilitate permanent locking of the
trunk lid for positive prevention of
access to trunk by unauthorized
persons.
Before leaving vehicle with an
attendant, lock trunk with master key
(square head) by turning key
clockwise to stop (tumbler slot
vertical), then provide attendant with
round-headed supplementary key.
Thus, the trunk lock has been
excluded from the operation of the
master lock system and cannot be
opened except with the square
headed master key.
To reverse this, turn trunk lock
counterclockwise back to horizontal
position of the tumbler slot with
master key. Lock will then be
reengaged in master lock system; that
is, it will automatically be locked or
unlocked depending on whether the
driver’s door is locked or unlocked.
The master lock system operates on
vacuum generated by the engine. A
reservoir allows the master lock
system to be actuated about five times
after the engine is turned off. If the
system can then no longer be
engaged, idle engine for a short
period.
If no vacuum is available, doors and
trunk have to be locked individually in
the normal manner. Thefuel tank filler
flap, however, remains unlocked.
Note:
If the filler flap cannot be opened
when the master lock system is
unlocked, refer to “Unlocking of the
Filler Flap”.

Seats
Front Seat Adjust ent
Forward and backward adjustment:
lift handle (1); slide seat to desired
position and allow handle to reen
gage.
Height of seat: raise lever (2); to raise
seat, move seat forward; to lower seat
move seat backward; allow lever to
reengage.
Seat back position: turn handwheel
(3) forward or backward.
For full reclining of backrest, seat
should be moved to one of the for-
wardmost positions and headrest
removed. For driving, return backrest
to upright position and push seat
back. Replace headrest.
Note:
Prior to operating the vehicle, the
driver should adjust the seat height
for proper vision as well as fore-aft
placement and seat back angle to
insure adequate control, reach,
operation, and comfort. The headrest
should also be adjusted for proper
height so that when the cushion is
tipped completely forward, it should
form a cradle behind the seat
occupant’s head. Both the inside and
outside rear view mirrors should then
be adjusted for adequate rearward
vision. Fasten seat belts. Children
under the age of six or under the
weight of 50 lbs. (23 kg) should be
seated in the back seat with an
approved restraint system properly
secured.
All seat, headrest, and rear view
mirror adjustments as well as
fastening of seat belts should be
accomplished before the vehicle is
put into motion.
Slafety Headrest
Adjust headrest to support the back of
the head atthe level of the upper end
of the ears. For height adjustment or
for removal, push headrest slightly
forward (1). To detach the headrest,
release arrester by depressing a
button located under the backrest
covering material. Button can be felt.
Front seats: button below L/H
headrest post (2).
Rear seats: button on top of backrest
between both headrest posts.
14

Seats
Ar Rest (Rear Seat)
A center arm rest is provided in the
rear seat which can be pulled out with
a loop.
For the removal of the rear seat
cushion see “Practical Hints” .
(
Safety Belts
Warning system:
The indicator marked “FASTEN SEAT
BELTS" is illuminated for 4— 8
seconds after turning the steering
lock key to position “2”. If the safety
belt of the driver’s seat is not fastened
a warning buzzer sounds
simultaneously.
Fastening of front and rear outer seat
belts (with inertia reel):
• Pull belt with tongue (1) across
shoulder and lap. The belt must
not be twisted and must be tight.
• Press tongue (1) into buckle (2)
and allow to engage audibly.
Unfastening, front and rear:
• Depress red button “PRESS" (3) in
buckle (2).
• Return tongue (1) to initial position.
15

Seats
>Operation of belts with inertia reel:
The safety belt inertia reel stops the
belt from unwinding further in case of
vehicle deceleration in any direction
or if the belt is pulled out quickly.
Functional test:
The locking function of the inertia reel
can be tested by braking, driving
around a bend or by pulling the belt
out quickly.
Fastening of rear center belt
(without inertia reel):
• Pull belt across the lap. It must not
be twisted and must be tight.
• Press tongue into buckle and allow
to engage audibly.
Adjustment of rear center seat belt:
To lengthen, turn belt buckle (on LH
side of belt) to be at right angles to the
belt and pull the tongue. To shorten,
pull loose end of belt.
Note:
No safety belt can be used for more
than one person. Belts are not
intended for children.
Anchoring points for a child seat are
provided.
After an accident, inspect the safety
belts and replace them, if required.
The belt anchors in the vehicle should
also be checked.
Belt webbing must not be routed via
sharp edges.
No modifications which may affect the
efficiency of the belts must be made.
For cleaning and care of belt webb
ing, refer to page 49.
16

Controls
Steering Lock
0 Steering is locked when the key is
removed. Key can be removed
only in this position.
Note:
Do not remove key from steering
lock while the vehicle is in motion
as this will cause the engagement
of thesteering lock thus rendering
the vehicle inoperable.
1 Steering is unlocked.
(If necessary, move steering
wheel slightly to turn the key
clockwise to position “ 1”).
2 Preglowing takes place.
Starting: continue turning key
clockwise to the stop. The starter
is engaged when the key is
pressed against the stop. The
starter nonrepeat unit requires
the key to be returned to position
"0” prior to a new starting at
tempt. For starting and turning off
the engine, refer to page 36.
Notes:
The following items can be operated
with the key in steering lock posi
tion “ 1”.
Wiper, windshield washer, headlight
flasher, electric lighter, glove
compartment light, radio, electric seat
heater for front seats.
The power supply to the standing
lights is disrupted if the key in the
steering lock is in position “2”.
A warning buzzer sounds when the
key has been left in steering lock
positions “ 1” or “0” and the driver's
door is opened.
<
Idle Speed Adjuster
To increase idle speed, turn knob
counterclockwise.
To decrease idle speed, turn knob
clockwise.
17

Controls
Light Switch
0 Off-position
1 Parking lights (includes side
marker lights, tail lights, license
plate lights, instrument panel
lights)
2 Same as pos. 1 plus headlights
3 Standing lights, right
4 Standing lights, left
A Turn to position 2 and pull out to
first detent = same as position 2
plus fog lights
B Available for an option
Note:
With the steering lock key removed
and the driver’s door open a signal
sounds if the vehicle’s exterior lighting
is not switched off (standing lights
excepted).

Controls
Co bination Switch
1 Low beam (turn light switch
clockwise two notches)
2 High beam (turn light switch
clockwise two notches)
3 Headlight flasher (high beam
available independent of light
switch position)
4 Turn signals, right
5 Turn signals, left
Control for windshield washer
system
When the washer system is
switched on, the wipers also
operate
Windshield wiper control
0 Windshield wiper switched off
1 Intermittent wiping
II Normal wiper speed
III High wiper speed
(
Tooperate the turn signals, move the
combination switch past the point of
resistance (up or down). The switch
is automatically cancelled when the
steering wheel is turned by a large
enough angle.
To signal minor directional changes
of the vehicle, such as changing
lanes on a highway, move combina
tion switch to the point of resistance
only and hold it there.
Hints:
If one of the turn signals fails, the turn
signal indicator system flashes and
sounds at a faster sequence than
under normal operating conditions.
Fog lights will only operate together
with low beam headlights. Fog lights
are turned off automatically when light
switch is returned to off-position.
19