Peterbilt Model 320 Operator's Manual after 8-07 - Peterbilt Motors ...

Water Temperature Gauge
cept for certain special engines. Check your engine manual
to be sure.
Engine Overheating
WARNING! Do not remove the radiator fill cap
while the engine is hot. Scalding steam and
fluid under pressure may escape and cause
serious personal injuries. You could be badly
burned.
• Wait until the coolant temperature is below
122°F (50°C).
• Protect face, hands, and arms by covering
the cap with a large, thick rag to protect
against escaping fluid and steam.
• Carefully and slowly turn the cap one-quarter
of a turn or until it reaches the first stop—
allowing excess pressure to escape—push
down and turn for final removal.
Wait until the coolant temperature is below 122° F (50° C).
Protect your face, hands, and arms by covering the cap
with a large, thick rag to protect you against escaping fluid
PART 4: CONTROLS AND DISPLAYS
and steam. Before you completely remove the cap, carefully
and slowly turn the cap part way to allow excess pressure
to escape. Then push down and turn for final removal.
The cooling system may overheat if the coolant level is
below normal or if there is a sudden loss of coolant (such
as a worn hose splitting). It may also temporarily overheat
during severe operating conditions such as climbing a long
hill on a hot day or stopping after high-speed driving.
If the “Engine Coolant Temperature” warning light comes
on, or you have any other reason to suspect the engine
may be overheating:
• Stop the vehicle, but DON’T TURN OFF THE ENGINE
unless a low water warning device indicates a loss of
coolant.
• With the transmission in neutral, check to be certain
the oil pressure gauge reads normal. Increase the
engine speed to about 1100 - 1200 RPM, maximum.
Return the idle speed to normal after 2 or 3 minutes.
If the warning light doesn’t go off or the temperature
gauge doesn’t begin to drop, then turn the engine off.
• If the overheating came from severe operating conditions,
the temperature should have cooled by this
– 50 – Y53-6015 R(08/07)