Chevrolet Low Cab Forward 4500 2019 Series Owner's Manual page 164

Warning (Continued)
We recommend that the exhaust
system and cab be inspected by
a competent technician:
Each time the vehicle has
an oil change.
Whenever a change is
noticed in the sound of the
exhaust system.
Whenever the exhaust
system, underbody or cab is
damaged or becomes
corroded.
To allow proper operation of your
vehicle's ventilation system, keep
the air inlet grille clear of snow,
leaves or other obstructions at all
times. Do not park with the
engine running or idle this vehicle
for more than 10 minutes with the
ventilation system control switch
in the OFF position. Even with the
ventilation system on, running the
engine while parked or stopped
(Continued)
Warning (Continued)
for longer periods of time is not
recommended. Entry of carbon
monoxide into the cab is possible
with a poorly repaired, damaged,
or corroded exhaust system or
cab. Do not run the engine in
confined areas (such as garages,
next to a building or near another
stopped vehicles with engine
running) any more than needed to
move the vehicle.
When the vehicle has to be
stopped in an unconfined area
with the engine running for any
more than a few minutes, take the
following steps:
Adjust the heating or cooling
system to force outside air
into the cab.
With temperature and outlet
selector knob in any
position:
(Continued)
Driving and Operating
Warning (Continued)
Set the air selector lever to
the fresh air position.
Set the fan speed control
knob to the maximum speed
position.
Keep the exhaust tailpipe
area clear of snow and
other material to help
reduce the buildup of
exhaust gases under the
vehicle.
This is particularly important when
parked in blizzard conditions. You
and others could be seriously
injured.
See Climate Control Systems 0 121
and Maintenance Schedule 0 269.
163