Engine Overheating - Chevrolet Low Cab Forward 4500 2019 Series Owner's Manual

Radiator Pressure Cap
The radiator cap, a 103 kPa (15 psi)
pressure type, must be installed
tightly, otherwise engine coolant
may be lost and damage to the
engine may result from overheating.
The radiator pressure cap should be
checked periodically for proper
operation. If a replacement is
required, a genuine GM part is
recommended.

Engine Overheating

When the Engine Overheats
The engine cooling system may
overheat if the engine coolant level
is too low, if there is a sudden loss
of engine coolant (such as radiator
hose failure), or if other problems
occur. It may also temporarily
overheat during severe operating
conditions such as:
Climbing a long hill on a hot day.
Stopping after high-speed
driving.
Idling for long periods in traffic.
If engine power drops and the
needle on the engine coolant
temperature gauge goes up above
the upper limit of the safety zone
and enters the "H" zone, the engine
is overheating. The engine overheat
warning light will come on. Either
steam or boiling engine coolant will
squirt out of the radiator. Take the
following corrective actions
immediately.
Warning
To help avoid being burned:
Do not tilt the cab or open the
engine access cover if you see or
hear steam or engine coolant
escaping from the engine
compartment. Wait until no steam
or engine coolant can be seen or
heard before tilting the cab or
opening the engine cover.
Do not remove the radiator cap or
engine coolant reserve tank cap if
the engine coolant in the tank is
boiling. Also do not remove the
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Vehicle Care
Warning (Continued)
radiator cap while the engine and
radiator are still hot. Scalding fluid
and steam can be blown out
under pressure if either cap is
taken off too soon.
You and others could be seriously
injured.
If Steam is Coming from the
Engine Compartment
Warning
If the engine coolant temperature
gauge shows an overheat
condition or you have other
reasons to suspect the engine
may be overheating, continued
operation of the engine (other
than as described here) even for
a short period of time may cause
a fire and the result in personal
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