trailer GMC ENVOY 1998 Owner's Manual

As shown in the chart, SAE SW-30 is best for your
vehicle. However, you can use
SAE low-30 if it’s going
to be 0°F (- 18°C) or above. These numbers on an oil
container show its viscosity, or thickness. Do
not use
other viscosity oils, such
as SAE 20W-SO.
NOTICE:
Use only engine oil with the American Petroleum
Institute Certified For Gasoline Engines
“Starburst”
symbol. Failure to use the
recommended oil can result in engine damage not
covered by your warranty.
GM Goodwrench@ oil meets all the requirements for
your vehicle.
If you are in an area where the temperature falls below
-20°F (-29”C), consider using either an SAE 5W-30
synthetic oil or an SAE OW-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures.
Engine Oil Additives
Don’t add anything to your oil. Your dealer is ready to
advise if you think something should be added.
When to Change Engine Oil
If any one of these is true for you, use the short tripkity
maintenance schedule:
0 Most trips are less than 5 to 10 miles (8 to 16 km).
This is particularly important when outside
temperatures are below freezing.
driving
in stop-and-go traffic).
off-road frequently. your vehicle.
or other commercial application.
0 Most trips include extensive idling (such as frequent
0 You operate your vehicle in dusty areas or
0 You frequently tow a trailer or use a carrier on top of
0 The vehicle is used for delivery service, police, taxi
Driving under these conditions causes engine oil
to
break down sooner. If any one of these is true for your
vehicle, then you need to change your
oil and filter
every
3,000 miles (5 000 km) or 3 months -- whichever
occurs first.
If none of them is true, use the long trip/highway
maintenance schedule. Change the oil and filter every
7,500 miles (12 500 km) or 12 months -- whichever
occurs first. Driving
a vehicle with a fully warmed
engine under highway conditions causes engine oil
to
break down slower.
6-13
ProCarManuals.com

A CAUTION:
Operating the engine with the air cleaner off can
cause you or others to be burned. The air cleaner
not only cleans the air, it stops flame
if the engine
backfires.
If it isn’t there, and the engine
backfires, you could be burned. Don’t drive with
it
off, and be careful working on the engine with
the
air cleaner off.
NOTICE:
If the air cleaner is off, a backfire can cause a
damaging engine fire. And, dirt can easily get
into your engine, which will damage it. Always
have the air cleaner in place when you’re driving.
Automatic Transmission Fluid
When to Check and Change
A good time to check your automatic transmission fluid
level
is when the engine oil is changed.
Change both the fluid and filter every
15,000 miles
(25 000 km) if the vehicle is mainly driven under one
or more of these conditions:
In heavy city traffic where the outside temperature
regularly reaches
90°F (32°C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or delivery service.
If you do not use your vehicle under any of these
conditions, change the fluid and filter every
50,000 miles (83 000 km).
See “Scheduled Maintenance Services’’ in the Index.
ProCarManuals.com

How to Check
Because this operation can be a little difficult, you
may choose to have this done at your
GM dealership
Service Department.
If you do it yourself, be sure
to follow all the
instructions here, or you could get
a false reading on
the dipstick.
NOTICE:
Too much or too little fluid can damage your
transmission.
Too much can mean that some of
the fluid could come out and fall on hot engine
parts or exhaust system parts, starting a fire.
Be
sure to get an accurate reading if you check your
transmission fluid.
Wait at least 30 minutes before checking the
transmission fluid level
if you have been driving:
When outside temperatures are above 90°F (32°C).
0 At high speed for quite a while.
0 In heavy traffic -- especially in hot weather.
While pulling a trailer.
To get the right reading, the fluid should be at
normal operating temperature, which is 180°F to
200°F
(82°C to 93°C). See “Checking Transmission Fluid
Hot”
in the Index.
6-16
ProCarManuals.com

Engine Compartment Fuse Block
The fuse block is under the hood at the driver’s side of
the engine compartment.
Remove the cover
by turning the fastener to the left. To
reinstall the fuse panel cover, push in and
turn the
fastener to
the right.
TRR TRN RTTRN STARTER
rRL BU
Name
TRL TRN
TRR TRN
TRL
BPU
VEH B/U
RT TURN
LT TURN
LT TRN
Usage
Trailer Left Turn
Trailer Right Turn
Trailer
Back-up Lamps
Vehicle Back-up Lamps
Right Turn Signal Front
Left Turn Signal Front
Left Turn Signal Rear
6-58
ProCarManuals.com

Name
RT TRN
RR PRK
TRL PRK
LT HDLP
RT HDLP
LT HI
RT HI
FR PRK
INT BAT
ENG
I
ECM B
ABS
ECM
1
HORN
BTS
I
BIU LP
IGN E
AIC
RAP
OXYSEN
Usage
Right Turn Signal Rear
Right Rear Parking Lamps
Trailer Park Lamps Left Headlamp
Right Headlamp
Left High Beam
Right High Beam
Front Parking Lamps
I/P Fuse Block Feed
Engine SensorsISolenoids, MAP,
CAM. PURGE, VENT
Engine Control Module, Fuel Pump,
Module, Oil Pressure
Anti-Lock Brake System
Engine Control Module Injectors Horn
Brake-Transmission Shift Interlock
Back-up
Lalllps
Engine
Air Conditioning
Retained Accessory Power
Oxygen Sensor
Name
IGN B
DRL
FOG LP
IGN
A
STUD #2
PARKLP
LR PRK
IGN C
HTDSEAT ATC
RRDFOG
HVAC
TRCHMSL
RR W/W
CRANK
LD LEV
HI BEAM
HAZLP
VECHMSL
HTDMIR
STOPLP
TBC
Usage
Column Feed, IGN 2, 3,4
Daytime Running Lamps
Fog Lamps
Starting and Charging IGN
I
Accessory Feeds, Electric Brake
Parking La~nps
Left Rear Parking Lamps Starter Solenoid, Fuel Pump. PRNDL
Heated Seat
Electronic Transfer Case
Rear Defogger
HVAC System
Trailer Center High Mount Stop Light
Rear Window Wiper
Clutch Switch, NSBU Switch
Electronic Load Leveling
HID Headlamps Hazard Lamps
Vehicle Center High
Mount Stop Lamp
Heated Mirror
Stoplamps
Truck Body Computer
6-59
1
ProCarManuals.com

Maintenance Schedule
I Short Trip/City Definition I
Follow the Short TripKity Maintenance Schedule if any
one of these conditions is true for your vehicle:
Most trips are less than 5 to 10 miles (8 to 16 km).
This is particularly important when outside
temperatures are below freezing.
Most trips include extensive idling (such as frequent
driving in stop-and-go traffic).
off-road frequently.
You operate your vehicle in dusty areas 6r
0 You frequently tow a trailer or use a carrier on top of
your vehicle.
or other commercial application.
If the vehicle is used for delivery service, police, taxi
One
of the reasons you should follow this schedule if
you operate your vehicle under any of these conditions
is that these conditions cause engine oil
to break
down soonel:
Short Trip/City Intervals
Every 3,000 Miles (5 000 km): Engine Oil and Filter
Change (or
3 months, whichever occurs first). Chassis
Lubrication (or
3 months, whichever occurs first). Drive
Axle Service (or
3 months, whichever occurs first).
Every 6,000 Miles (10 000 km): Tire Rotation.
Every 15,000 Miles (25 000 km): Air Cleaner Filter
Inspection,
if driving in dusty conditions. Automatic
Transmission Service (severe conditions only).
Every 30,000 Miles (50 000 km): Air Cleaner Filter
Replacement. Fuel Filter Replacement.
Every 50,000 Miles (83 000 km): Automatic
Transmission Service (normal conditions).
Every 60,000 Miles (100 000 km): Engine
Accessory Drive Belt Inspection. Fuel Tank, Cap and
Lines Inspection.
Every 100,000 Miles (166 000 km): Spark Plug Wire
Inspection. Spark Plug Replacement. Positive
Crankcase Ventilation (PCV) Valve Inspection.
(Continued)
-- 7-5
ProCarManuals.com

Maintenance Schedule
I Short Trip/City Intervals I
Every 150,000 Miles (240 000 km): Cooling System
These intervals only summarize maintenance services.
Be sure to follow the complete maintenance schedule on
the following pages. Service
(or every
60 months, whichever occurs first).
1 Long TridHiEhwav Definition
Follow this maintenance schedule only if none of the
conditions from the Short Trip/City Maintenance
Schedule is true. Do not use this schedule
if the vehicle
is used for trailer towing, driven in a dusty area or used
off paved roads. Use the Short TripKity schedule for
these conditions.
Driving a vehicle with a fully warmed engine under
highway conditions causes engine oil
to break
down slower:
Long TridHiehwav Intervals
Every 7,500 Miles (12 500 km): Engine Oil and Filter
Change (or every 12 months, whichever occurs first).
Chassis Lubrication (or every 12 months, whichever
occurs first). Drive Axle Service. Tire Rotation.
Every 15,000 Miles (25 000 km): Automatic
Transmission Service (severe conditions only).
Every 30,000 Miles (50 000 km): Fuel Filter
Replacement. Air Cleaner Filter Replacement.
Every 50,000 Miles (83 000 km): Automatic
Transmission Service (normal conditions).
Every 60,000 Miles (100 000 km): Engine
Accessory Drive Belt Inspection. Fuel Tank, Cap and
Lines Inspection.
Inspection. Spark Plug Replacement. Positive
Crankcase Ventilation (PCV) Valve Inspection.
Every 150,000 Miles (240 000 km): Cooling System
Service (or every
60 months, whichever occurs first).
These intervals only summarize maintenance services.
Be sure to follow the complete maintenance schedule
on
the following pages.
Every 100,000 Miles (166 000 km): Spark Plug Wire
7-6 I
~ 1 I
ProCarManuals.com

Short TripKity Maintenance Schedule I
The services shown in this schedule up to 100,000 miles
( 166 000 km) should be performed after 100,000 miles
( 166 000 km) at the same intervals. The services shown
at
150,000 miles (240 000 km) should be performed at
the same interval after 150,000 miles (240
000 ktn).
See “Owner Checks and Services” and “Periodic
Maintenance Inspections” following.
Footnotes
7 The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure
to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to the
completion
of the vehicle’s ~1sefu1 life. We, however.
urge that all recommended maintenance services be
performed
at the indicated intervals and the maintenance
be recorded.
## Lubricate the front suspension, ball joints, steering
linkage, parking brake cable guides, propshaft splines.
universal joints and brake pedal springs.
+ A ~ood time to check your brakes is during tire
rotation. See “Brake System Inspection” under ”Periodic
Maintenance Inspections”
in Part C of this schedule.
.:. .:, -,-*,- Drive axle service (see “Recommended Fluids and
Lubricants“ in the Index for proper lubricant to use):
Locking Differential -- Drain fluid and refill at first
engine oil change.
At subsequent oil changes. check
fluid level and add fluid
as needed. If driving in
dusty areas or towing a trailer, drain fluid and refill
every 15,000 miles
(25 000 km).
Standard Differential -- Check fluid level and add
fluid
as needed at every oil change. If driving in
dusty areas or towing a trailer. drain fluid and refill
every
15,000 miles (25 000 km).
More frequent lubrication may be required for
hea\jy-duty
or off-l-oad use.
7-7
ProCarManuals.com

1 Short TripKity Maintenance Schedule I
27,000 Miles (45 000 kin) (Continued)
0 Lubricate chassis components (or every 3 months, whichever occurs first).
0 Check readfront axle fluid level and add fluid as needed. Check constant
(See footnote
#.)
velocity
joints and axle seals for leaking. (See footnote **.)
30,000 Miles (50 000 km)
0
0
0
0
Change engine oil and filter (or every 3 months, whichever occurs first).
An Emission Control Service.
Lubricate chassis components (or every
3 months, whichever occurs first).
(See footnote
#.)
Check readfront axle fluid level and add fluid as needed. Check constant
velocity joints and axle seals for leaking. (See footnote
**.)
Replace fuel filter.
An Emission Control Service. (See footnote?.)
Replace air cleaner filter.
An Emission Control Service.
Change automatic transmission fluid and filter if the vehicle is mainly driven
under one or more of these conditions:
7-12
In heavy city traffic where the outside temperature regularly reaches 90°F
(32°C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
I i
DATE I
I MILEAGE ACTUAL I SERVICEDBY: I
ProCarManuals.com

Short TripKity Maintenance Schedule
0 Check readfront axle fluid level and add fluid as needed. Check constant
0 Change automatic transmission fluid and filter if the vehicle is mainly driven
velocity
joints and axle seals for leaking. (See footnote
**.)
under one or more of these conditions:
- In heavy city traffic where the outside temperature regularly reaches 90°F
- In hilly or mountainous terrain.
(32 "C) or higher.
- When doing frequent trailer towing.
- Uses such as found in taxi, police or delivery service.
If you do nut use your vehicle under any of these conditions, change the fluid
and filter every 50,000 miles (83 000 km).
Inspect air cleaner filter if you are driving in dusty conditions. Replace filter
if necessary.
An Emission Control Service. (See footnote?.)
48,000 Miles (80 000 km)
0 Change engine oil and filter (or every 3 months, whichever occurs first).
Lubricate chassis components (or every 3 months, whichever occurs first).
An Emissiorz Control Service.
(See footnote
#.)
DATE I
(Continued)
7-15
ProCarManuals.com