GMC MOTORHOME 1978 User manual

A Word To
The
GMC Motorhome Owner ...
Congratulations on your purchase of a GMC Motorhome . You have
opened the way to an endless variety of
happy holidays .
This manual has been prepared to acquaint you with the operation
and maintenance of your Motorhome, and to provide important safety
information . It is supplemented by two convenient folders which provide
additional information on vehicle maintenance and warranties . We urge
you to read these three publications carefully . Follow the recommen-
dations to help assure the most enjoyable and troublefree operation of
your vehicle .
While reading this manual you will notice that some specifications
are given in both metric and customary units . Where
precise accuracy is
not needed, some conversions have been
rounded to even numbers for
your handy use .
An Operating Manual Appendix
is
provided with
vehicles
built
after
January 1, 1978, which have
a gross vehicle weight rating (GVWR) in
excess of 10,000 pounds . This
Appendix covers items relating to com
pliance with Federal noise
emission standards and includes the noise
emission
warranty . It also contains information on maintenance of the
noise control system
and lists acts which are considered to be tampering
with the system . As noted
in the Appendix, tampering with the noise
control system is prohibited by
Federal Law .
When it comes to service, remember
that your GMC Motorhome
Dealer knows your vehicle best .
Your
dealer is
interested in your com-
plete satisfaction . Return to him for Guardian
Maintenance Service and
any other repairs you may require .
To assist dealers in
handling your needs GMC Truck and Coach
maintains a
number of Zone Offices throughout the country . If you have
a problem that has not been
handled
to
your satisfaction, please follow
the procedure described under the
"Owner Assistance" section .
Thank you for choosing
a
GMC
Motorhome . We extend our best
wishes for many years of pleasant traveling .
Cordially,
General Sales
Manager

1978
GMC
MOTORHOME
OPERATING
MANUAL
IMPORTANT
This manual should be considered a
permanent
part of the vehicle . It should remain
with the
vehicle when sold, to provide the next owner
with
important safety, operating and
maintenance
information .
All information, illustrations and specifications
contained in this manual are based on the latest
product
information available at the time of
printing
. The right is reserved to make changes
at any
time
without notice .
For
vehicles sold in Canada, substitute the
name General Motors of Canada Limited when-
ever the
name GMC Truck & Coach Division
appears in this manual .
Service Publications
GMC TRUCK & COACH DIVISION
GENERAL MOTORS CORPORATION
Pontiac,
Michigan 48053
X-7821 A
Part No . 2028572

TABLE OF CONTENTS
SUBJECT
PAGE NO . SUBJECT
PAGE
NO .
Important
Information on
Cruise Control . . . . . . . . . . . . . . . . . 19
Vehicle Loading . . . . . . . . . . . . . . . . . . .
1
Floor Controls . . . . . . . . . . . . . . . . ..
. 21
Before Driving Your Motorhome . . . . . . . . .
3
Power Brake System . . . . .. ...
. . . 21
Driver Checklist . . . . . . . . . . . . . . . . . .
3
Headlight Dimmer Switch
. . . . . . . . .
22
Guard Against Theft . . . . . . . . . . . . . . .
3
Headlight "Flicker . . . . . . . . ... ... .. 22
Inside Rearview Mirror . . . . . . . . . . .
. . 4
InstrumentPanel and Controls . . . . . . . 22
Outside Rearview Mirror . . . . . . . . . . .
. 4 Speedometer
and Odometer . . . . ... 22
Keys . . . . . . . . . . . . . . . . . . .
. . . . . . 4 Fuel Gauge . . . . . . . . .
. . . . . . . . . . . 22
Entrance Door . . . . . . . . . . . . . . . . . . . 4
Temperature Gauge . . . . . . . . . . . .
. 22
Seats
. . . . . . . . . . . . . . . . . . . . . . . . . . 5
Oil Pressure Gauge . . . . . . . . . . . . . .
23
Head
Restraint for Dual Passenger Seat . 8
Charging System Warning
Light
. . .
. 23
Belt Restraints . . . . . . . . . . .
. . . . . . . . 9
Brake System Warning Light . . . . . . 24
Restraint of Pregnant Women . . . .
.
.
. . 9
Tell-Tale Warning Light Cluster . . . . 24
Lap Belt Inspection . . . . . . . . . . . . . . .
10 Voltmeter . . . . . . . . . . . . . . . . . .
. . . 25
Child Restraint . . . . . . . . . . . . . . . . .
. . 10 Headlight
Switch
. . . . . . . . . . . . . .
. 25
Trailer Towing . . . .
. . . . . . . . . . . . . . . 10 Windshield
Wiper Lever . . . . . . . . . . 25
Operation
In Foreign Countries . . . . . . . 11
Windshield Washers . . . . . . . . . . . . . 25
Trip Tips .
. .
.. .
. . .
.
. . . . . . . . . . . . . 12 Fuel
Selector Switch
. ..
. . . . . . . . . . 26
Driving Tips . . . . . . . . .
. . . . . . . . . . . . 13 Battery Boost Switch . . . . . . . . . . . .
. 26
Starting and Operating
Vehicle . . . . . . . . . 15
Cigar-Cigarette Lighter . . . . . . . . . .
. 26
Engine
Exhaust
Gas
Caution . . . . . . . . 15 Automotive
Heating and Air
Conditioning System . . . . . . . . . . .
26
Steering Column Controls . . . . . . . . . .
16
Anti-Theft Steering Column Lock . . .
16
Radios and Tape Player . . . . . . . . . . 27
Guard Against Theft . . . . . . . . . . . . . 16
Mobile Radio Systems . . . . . . . . 30
Parking . . . . . . . . . . . . . . . . . . . . . . 17
Electro-Level System . . . . . . . . . . . . 30
Starting the Engine
.
. . . . . . . . . . . . 17
Operation of Living Area
Facilities . . . . . . . 33
New Vehicle "Break-In" Period . . . . . 17 Living Area Facilities Caution . . . . . . . 33
Automatic Transmission . . . . . . . . . . 18
Living Area Electrical System . . . . . . . . 33
Turn Signal Lever
. . .
. . . . . . . . . . . 18
General Information
. . . . . .
.
..
. . . . 33
HazardWarning Flasher . . . . . . . . . . 19
120-Volt
To 12-Volt
Converter
Horn Control . . . . . . . . . . . . . . . . . . 19
and Battery Charger . . . . . . . . . . 34
Power Steering
. . . . .
. . . . . . . . . . . . 19 External Power . . . . . . . . . . . . . . . . .
34
Tilt Steering
Wheel . . . . . . . . . . . . . 19 Lighting System . . . . . . . . . . . . . . . . 35

SUBJECT

PAGE NO .
Monitor Panel
. . . . . . . . . . . . . . . . . 35
Motor
Generator . . . . . . . . . . . . . . . 36
Exterior
Receptacle . . . . . . . . . . . . . 37
Living Area WaterSystem . . . . . . . . . .
38
Filling Water Tank . . .
. . . . . . . . . . 38
External Water Connection . . . . . .
. 38
Water Pump . . . . . . . . . . . . . . .
. . . .

39
Water Heater . . . . . . . . . . . . . .
. . . .
40
Kitchen
Facilities . . . . . . . . . . . . . . . . . 41
All-Electric Refrigerator . . . . . . . . . . 41
PowerRange
Hood . . . . . . . . . . . . . 42
L .P . Gas
Kitchen Range/Oven . . . . . 42
L .P .
Gas Cook Top . . . . . . . . . . . . . . 44
Microwave
Oven . . . . . . . . . . . . . . . 45
Kitchen Sink and Faucet . . . . . . . . . .

54
Water Treatment Unit . . . . . . . . . . . 55
Bathroom
Facilities . . . . . . . . . . . . . . . 55
Standard
Toilet
. . . .
. . . . . . . . . . . . 55
Recirculating Toilet .
. . . . . . . . . . . . 56
Bathroom Sink and
Shower Control Valve . . . . . . . . . .

5 7
Bathroom Warm Air Duct . . . . .
. . . .

5 7
Bathroom Exhaust Vent and
Fan . . . . 57
Ventilation . . . . . . . . . . . . . . . . . . . . . . 58
Windows . . . . . . . . . . . . . . . . . . . . . 58
Ceiling Vents . . . . . . . . . . . . . . . . . . 59
Roof-Mounted Air Conditioner . . . . . . .
60
Emergency Starting .. ..
. . . . . . . . . . . 71
Jump Starting . . . . . . . . . . . . . . .
. . . . 71
TABLE OF
CONTENTS
SUBJECT

PAGE NO .
Engine Coolant . . . . . . . . . .
. . . . . . . . .
73
Engine
Coolant Caution . . . . . . . . . . . . 73
Jack Usage Instruction . . . . . . . . . . . . . 74
Towing . . . . . . . . . .
. . . . . . . . . . . . . . . 76
Freeing Vehicle
From Sand, Etc . . . . . . .

77
Rear Suspension
Failure . . . . . . . . . . . . 77
Emergency Exit . . . . . . . . . . . . . . . . . .
78
Fire Extinguisher . . . . . . . . . . . . . . . . .
79
Appearance Care . . . . . . . . . . . .. . .
. . . . 81
Care and Cleaning of Interior . . . . . . . . .

81
Cleaning Fabrics
(With Foam-Type Cleaner) . . . . . 81
Cleaning Fabrics
(With Solvent-Type Cleaner) . . . .

82
Removal of Specific Stains . . . . . . . . .

82
CleaningLeather or Vinyl
Trim
. . . .

82
Seat Belt Care . . . . . . . . . . . . . . . . .
82
Glass

Surfaces . . . . . . . . . . . . . . . . . .

82
Vacuum
Cleaner
. . . . . . . . . . . . . . . .
84
Draperies . . . . . . . . . . . . . . . . . . . . .
85
Kitchen Sink . . . . . . . . . . . . . . . . . . .

85
Power Range
Hood Filter . . . . . . . . . 85
L .P . Gas Range/Oven . . . . . . . . . . ..
85
L .P . GasCook Top . . . . . . . . . . . . . .

86
Microwave Oven . . . . . . . . . . . . . . . 86
Exterior Appearance Care . . . . . . . . . . .
86
Washing . . . . . . . . . . . . . . . . . . . . . .
86
Cleaning White
Sidewall Tires . . . . . . 87
Underbody Maintenance . . . . . . . . . . 87
Furnace . . . . . . . . . . . . . . . . . . . . . . . . 61
Polishing and Waxing . . . . . . . . . . .
. 86
Protection of Exterior
Furniture . . . . . . . . . . . . . . . . . . . . . . .
63
Bright Metal Parts . . . . . . . . . . .
. 87
In
Case of Emergency . . . . . . . . . . . . . . . . 71
Foreign Material Deposits . . . . . . . . . 87
Four-Way Hazard Warning Flasher . . . . 71 Finish
Damage . . . . . . . . . . . . . . . . . 87

SUBJECT

PAGE NO .
Undercoating . . . . . . . . . . . . . . . . . . 87
GM Appearance Care and
Maintenance Materials . . . . . . . . . 88
Service and Maintenance . . . . . . . . . . . . . . 89
Maintenance Schedule
. . . . . . . . . . .
. . 89
NIASE Mechanic Certification . . . . . . . 89
Accessibility
. . . . . . . . . . . . . . . . . . . . .
90
Exterior Compartments . . . . . . . . . .
90
Engine Accessibility . . . . . . . . . . . . . 93
Engine Compartment Light . . . . . . . .

93
Hoisting Instructions . . . . . . . . . . . . . . .
93
Lubrication Details . . . . . . . . . . . . . . . .
94
Engine . . . . . . . . . . . . . . . . . . . . . . . 94
Transmission . . . . . . . . . . . . . . . . . .
96
Final Drive . . . . . . . . . . . . . . . . . . . . 97
Steering System . . . . . . . . . . . . . . . .
98
BrakeSystem . . . . . . . . . . . . . . . . . . 98
Servicing Details
. . . . . . . . . . . . . . . . . .
99
Engine Cooling System . . . . . . . . . . . 99
EngineFuel System . . . . . . . . . . . . .
101
Carburetor . . . . . . . . . . . . . . . . . . .
.102
Engine
Air Cleaner . . . . . . . . . . . . . . 102
Chassis
Electrical System . . . . . . . . . 102
Wheels and Tires
.
. . . . . . . . . . . . . . 104
Wheel Bearings
. . . . . . . . . . . . . . . . 108
Front Suspension
. . . . . . . . . . . . . . . 108
TABLE OF CONTENTS
SUBJECT

PAGE
NO .
Rear Suspension
. . . . . . . . . . . . . .
. .
109
L .P . Gas System
. . .. ... . . . . . . . . .
111
Living Area Electrical System . . . . . . 112
Onan Motor Generator Maintenance . 116
Standard Toilet

. . . . . . . . . . . . . . . . 118
Recirculating Toilet . . . . . . . . . . . . . 119
Draining Holding Tank . . . . . . . . . . . 120
Draining Living Area Water System . .120
Water Tank Filter . . . . . . . . . . . . . . 121
Sanitizing Living Area
Water System

. . . . . . . . . . . . . . . 122
Winterization . . . . . . . . . . . . . . . . . .123
Vehicle Storage
.
. . . . . . . . . . . . . . . 123
Vehicle Trip Preparation . . . . . . . . . 125
General Data and Specifications . . . . . . . . . 129
Owner Assistance . . . . . . . . . . . . . . . . . . . 137
U .S . Zone Territories . . . . . . . . . . . . . . . 138
U .S . Zone Offices . . . . . . . . . . . . . . . . . . 139
General
Motors Overseas Offices
. . . .
. . 139
GM of Canada Limited-Zone Offices . . .
140
After-Hour Information Service . . . . . . . 141
Emergency Service
. . . . . . . . . . . . . . . . 141
Maintenance Manual
and Parts Book . . 141
Facts About Gasoline Mileage . . . ..
. .
142
Index (Alphabetical )

. . . . . . . . . . . . . . . . . 143
Gas Station Information . . Inside Back Cover