Chevrolet Low Cab Forward 4500 2019 Series Owner's Manual page 206

Warning
Even when the engine has been
stopped, the engine coolant in the
radiator remains under pressure.
Immediately removing the radiator
cap could cause steam or hot
water to blow out, and you could
be scalded as a result. The
engine coolant in the reserve tank
may also be hot. Immediately
removing the cap could cause hot
water to blow out, and possibly
scald you. Perform inspection,
refilling, and replacement of
coolant only when its temperature
has cooled.
When removing the radiator cap
and reserve tank cap, use a thick
cloth to cover the cap and turn it
little by little.
You and others could be seriously
injured.
4. If no steam or engine coolant
can be seen or heard from the
engine compartment:
Tilt the cab or open the
engine access cover.
If the engine coolant is
boiling, wait until it stops
before proceeding.
Look at the see-through
reserve tank. The
engine coolant level
should be between the
"MAX" and "MIN" lines
on the reserve tank.
If necessary, pour
engine coolant (See
Engine Coolant 0 198
for the proper coolant
and water mixture) into
the reserve tank only,
not directly into the
radiator. Also, do not
check engine coolant
level at the radiator.
Make sure the fan belts are
not broken, or off the
pulleys, and that the fan
turns when the engine is
Vehicle Care
started. Make sure the fan
blade and pulleys are not
broken.
If the engine coolant level in
the reserve tank is low, look
for leaks at the radiator
hoses and connections,
heater hoses and
connections, radiator, and
water pump.
If the engine coolant level in
the reserve tank is at the
correct level but there is still
an indication on the
instrument panel of an
overheat condition:
You must let the engine
cool first. You may then add
engine coolant directly to
the radiator. See "Adding
Engine Coolant" under
Engine Coolant 0 198.
5. Inspect to see if there is any
dirt, etc. attached to the front
surface of the radiator. Also,
inspect to see if there is
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