Page 273 of 412

6-4
In Canada, look for the
ªAuto Makers' Choiceº
label on the fuel pump.
Canada Only
Be sure the posted octane is at least 87. If the octane is
less than 87, you may get a heavy knocking noise when
you drive. If it's bad enough, it can damage your engine.
If you're using fuel rated at 87 octane or higher and you
hear heavy knocking, your engine needs service. But
don't worry if you hear a little pinging noise when
you're accelerating or driving up a hill. That's normal,
and you don't have to buy a higher octane fuel to get
rid of pinging. It's the heavy, constant knock that means
you have a problem.If your vehicle is certified to meet California Emission
Standards (indicated on the underhood emission control
label), it is designed to operate on fuels that meet
California specifications. If such fuels are not available
in states adopting California emissions standards, your
vehicle will operate satisfactorily on fuels meeting
federal specifications, but emission control system
performance may be affected. The malfunction indicator
lamp on your instrument panel may turn on and/or your
vehicle may fail a smog
-check test. See ªMalfunction
Indicator Lampº in the Index. If this occurs, return to
your authorized GM dealer for diagnosis to determine
the cause of failure. In the event it is determined that the
cause of the condition is the type of fuels used, repairs
may not be covered by your warranty.
Some gasolines that are not reformulated for low
emissions may contain an octane
-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl (MMT);
ask your service station operator whether or not the fuel
contains MMT. General Motors does not recommend the
use of such gasolines. If fuels containing MMT are used,
spark plug life may be reduced and your emission control
system performance may be affected. The malfunction
indicator lamp on your instrument panel may turn on.
If this occurs, return to your authorized GM dealer
for service.
Page 276 of 412

6-7
When you put the cap back on, turn it to the
right (clockwise) until you hear a clicking sound. Make
sure you fully install the cap. The diagnostic system can
determine if the fuel cap has been left off or improperly
installed. This would allow fuel to evaporate into the
atmosphere. See ªMalfunction Indicator Lampº in
the Index.
NOTICE:
If you need a new cap, be sure to get the right
type. Your dealer can get one for you. If you get
the wrong type, it may not fit properly. This may
cause your malfunction indicator lamp to light
and your fuel tank and emissions system may be
damaged. See ªMalfunction Indicator Lampº in
the Index.
Filling a Portable Fuel Container
CAUTION:
Never fill a portable fuel container while it is in
your vehicle. Static electricity discharge from the
container can ignite the gasoline vapor. You can
be badly burned and your vehicle damaged if this
occurs. To help avoid injury to you and others:
Dispense gasoline only into
approved containers.
Do not fill a container while it is inside a
vehicle, in a vehicle's trunk, pickup bed or
on any surface other than the ground.
Bring the fill nozzle in contact with the
inside of the fill opening before operating
the nozzle. Contact should be maintained
until the filling is complete.
Don't smoke while pumping gasoline.
Page 311 of 412

6-42 Inflation -- Tire Pressure
The Certification/Tire label, which is on the rear edge of
the driver's door, shows the correct inflation pressures
for your tires when they're cold. ªColdº means your
vehicle has been sitting for at least three hours or driven
no more than 1 mile (1.6 km).
NOTICE:
Don't let anyone tell you that underinflation or
overinflation is all right. It's not. If your tires
don't have enough air (underinflation), you can
get the following:
Too much flexing
Too much heat
Tire overloading
Bad wear
Bad handling
Bad fuel economy.
NOTICE: (Continued)
NOTICE: (Continued)
If your tires have too much air (overinflation),
you can get the following:
Unusual wear
Bad handling
Rough ride
Needless damage from road hazards.
When to Check
Check your tires once a month or more. Also, check the
tire pressure of the spare tire.
How to Check
Use a good quality pocket
-type gage to check tire
pressure. You can't tell if your tires are properly inflated
simply by looking at them. Radial tires may look
properly inflated even when they're underinflated.
Be sure to put the valve caps back on the valve
stems. They help prevent leaks by keeping out
dirt and moisture.
Page 336 of 412
6-67
Capacities and Specifications
All capacities are approximate. When adding, be sure to fill to the appropriate level or as recommended in
this manual.
See refrigerant charge label under the hood for charge capacity information and requirements.
Engine Identification -- Gasoline Engines
EngineªVORTECº 4300 ªVORTECº 5000 ªVORTECº 5700 ªVORTECº 8100
Type V6 V8 V8 V8
VIN Code W M R G
Fuel System CSFI
1CSFI1CSFI1MFI2
Spark
Plug Gap0.060 inches
(1.52 mm)0.060 inches
(1.52 mm)0.060 inches
(1.52 mm)0.060 inches
(1.52 mm)
Firing Order
1
-6-5-4-3-21-8-4-3-6-5-7-21-8-4-3-6-5-7-21-8-7-2-6-5-4-3
1Central Sequential Fuel Injection
2Sequential Fuel Injection
Page 338 of 412
6-69 Crankcase Capacity
ENGINE VIN Quantity With Filter
ªVORTECº 4300 V6 W 4.5 quarts (4.3 L)
ªVORTECº 5000 V8 M 5.0 quarts (4.8 L)
ªVORTECº 5700 V8 R 5.0 quarts (4.8 L)
ªVORTECº 8100 V8 G 6.5 quarts (6.15 L)
After refill, the level MUST be rechecked. Add enough engine oil so that the fluid is within the proper operating
range. Variation in oil filter size and oil cooler drainback can cause different fill levels. See ªEngine Oilº in the Index.
Fuel Tank Capacity
TYPE QUANTITY MODEL TYPE
Standard Tank 31.0 U.S. gallons (117.3 L) Passenger and Cargo
Standard Tank 35.0 U.S. gallons (132.5 L) Cab and Chassis
Optional Tank* 55.0 U.S. gallons (208.1 L) Cab and Chassis
*159 inch wheelbase or 177 inch wheelbase