2002 GMC ENVOY Owner's Manual

5-15
3. Fill the radiator with the proper DEX-COOL

coolant mixture, up to the base of the filler neck. See
ªEngine Coolantº in the Index for more information
about the proper coolant mixture.
4. Then fill the coolant recovery tank to the FULL
COLD mark.
5. Put the cap back on the coolant recovery tank, but
leave the radiator pressure cap off.

5-16
6. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for the
engine cooling fan.
7. By this time, the coolant level inside the radiator
filler neck may be lower. If the level is lower, add
more of the proper DEX
-COOL
coolant mixture
through the filler neck until the level reaches the
base of the filler neck.
8. Then replace the pressure cap. At any time during
this procedure if coolant begins to flow out of the
filler neck, reinstall the pressure cap. Be sure the
pressure cap is hand
-tight.

5-17
Engine Fan Noise
This vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions the clutch is not engaged. This improves
fuel economy and reduces fan noise. Under heavy
vehicle loading, trailer towing, and/or high outside
temperatures, the fan speed increases when the clutch
engages. So you may hear an increase in fan noise.
This is normal and should not be mistaken as the
transmission slipping or making extra shifts. It is merely
the cooling system functioning properly. The fan will
slow down when additional cooling is not required and
the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch disengages.
If a Tire Goes Flat
It's unusual for a tire to ªblow outº while you're driving,
especially if you maintain your tires properly. If air goes
out of a tire, it's much more likely to leak out slowly.
But if you should ever have a ªblowout,º here are a few
tips about what to expect and what to do:
If a front tire fails, the flat tire will create a drag that
pulls the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
A rear blowout, particularly on a curve, acts much like a
skid and may require the same correction you'd use in a
skid. In any rear blowout, remove your foot from the
accelerator pedal. Get the vehicle under control by
steering the way you want the vehicle to go. It may be
very bumpy and noisy, but you can still steer. Gently
brake to a stop
-- well off the road if possible.
If a tire goes flat, the next part shows how to use your
jacking equipment to change a flat tire safely.

5-18
Changing a Flat Tire
If a tire goes flat, avoid further tire and wheel damage
by driving slowly to a level place. Turn on your hazard
warning flashers.
CAUTION:
Changing a tire can cause an injury. The vehicle
can slip off the jack and roll over you or other
people. You and they could be badly injured.
Find a level place to change your tire. To help
prevent the vehicle from moving:
1. Set the parking brake firmly.
2. Put the shift lever in PARK (P).
3. If you have a four
-wheel-drive vehicle,
be sure the transfer case is in a drive
gear
-- not in NEUTRAL.
CAUTION: (Continued)
CAUTION: (Continued)
4. Turn off the engine.
5. Put the wheel blocks at the front and
rear of the tire farthest away from the
one being changed. That would be the
tire on the other side of the vehicle, at
the opposite end.
The following steps will tell you how to use the jack and
change a tire.

5-19 Removing the Spare Tire and Tools
The jacking equipment you will need is stored under the
rear seat of the vehicle. See ªRear Seatsº in the Index
for more information on accessing the jacking
equipment under the rear seat.
The tools you'll be using include the wheel wrench (A),
tire blocks (B), extension (socket end) (C), handle
(jack end) (D), and jack (E).
The following instructions explain how to remove the
spare tire mounted underneath your vehicle.
NOTICE:
Never remove or restow a tire from/to a stowage
position under the vehicle while the vehicle
is supported by a jack. Always tighten the tire
fully against the underside of the vehicle
when restowing.

5-20
1. To remove the underbody-mounted spare, insert the
socket end of the extension, on an angle, into the
hole in the rear bumper. Be sure the socket end of
the extension connects into the hoist shaft.
2. Turn the wheel wrench counterclockwise to lower
the spare tire. Keep turning the wheel wrench
until the spare tire can be pulled out from under
the vehicle.If the spare tire does not lower to the ground, the
secondary latch is engaged causing the tire not to
lower. See ªSecondary Latch Systemº later in
this section.
When the tire has been completely lowered, tilt
the retainer at the end of the cable and pull it through
the wheel opening. Pull the tire out from under
the vehicle.
NOTICE:
To help avoid vehicle damage, do not drive the
vehicle before the cable is properly stored.
3. Put the spare tire near the flat tire.
4. Use the chisel end of the wheel wrench to pry off the
center cap.
See ªRemoving the Flat Tire and Installing the
Spare Tireº later in this section to continue changing
the flat tire.

5-21
Secondary Latch System
The spare tire hoist assembly is equipped with a
secondary latch system. It's designed to stop the spare
tire from suddenly falling off your vehicle. For the
secondary latch to work, the spare tire must be stored
with the valve stem pointing up. See ªStoring a Flat or
Spare Tire and Toolsº in the Index for instructions on
storing the spare tire correctly.
CAUTION:
Before beginning this procedure read all the
instructions. Failure to read and follow the
instructions could damage the hoist assembly and
you and others could get hurt. Read and follow
the instructions listed below.
To release the spare tire from the secondary latch do
the following:
1. Check under the
vehicle to see if the
cable is visible.
2. If it is not visible, proceed to Step 6.
If visible, first try to tighten the cable by turning the
wheel wrench clockwise until you hear two clicks or
feel it skip twice. You cannot overtighten the cable.
3. Loosen the cable by turning the wheel wrench
counterclockwise three or four turns.
4. Repeat this procedure at least two times.
If the spare tire lowers to the ground, continue with
Step 2 of ªRemoving the Spare Tire and Toolsº
earlier in this section.
5. Turn the wrench counterclockwise until
approximately 6 inches (15 cm) of cable is exposed.

5-22
6. Attach the jack handle, extension and the wheel
wrench to the jack and place it under the vehicle
towards the front of the rear bumper. Position the
center lift point of the jack under the center of the
spare tire.
7. Turn the wrench clockwise to raise the jack until it
lifts the end fitting.8. Continue raising the jack until the spare tire stops
moving upward and is held firmly in place. The
secondary latch has released and the spare tire is
balancing on the jack.
9. Lower the jack by turning the wheel wrench
counterclockwise. Keep lowering the jack until
the spare tire slides off the jack or is hanging by
the cable.
CAUTION:
Someone standing too close during the procedure
could be injured by the jack. If the spare tire does
not slide off the jack completely, make sure no
one is behind you or on either side of you as you
pull the jack out from under the spare.
10. Disconnect the jack handle from the jack and
carefully remove the jack. Use one hand to push
against the spare while firmly pulling the jack out
from under the spare tire with the other hand.