Radiator Pressure Cap - Chevrolet 1970 Owner's Manual

additional protectIOn against freezing
at temperatures lower than -20°F,
(-32 °F in Canada), a sufficient
amount of an ethylene glycol base
coolant meeting GM Specification
1899-M should be used.
NOTE: Alcohol or methanol base cool-
ants or plain water are not recommended
for your Chevrolet at any time.
Thermostat
The cooling ~ystem is protected and
controlled by a thermostat installed in
the engine coolant outlet to maintain
a satisfactory operating temperature
of the engine. This thermostat
is
de-
signed for continuous use through
both winter and summer and need not
be changed seasonally. When replace-
ment is necessary, specify United
Delco parts.
Radiator Pressure Cap
The radiator cap, a 15 lb. pressure
type, must be installed tightly, other-
wise coolant may be lost and damage
to engine may result from overheating.
Radiator pressure caps should be
checked periodically for proper oper-
ation. If replacement is required spec-
ify AC.
To completely drain the cooling
system: The cooling system should be
flushed with plain water after each
coolant drain.
• All models-remove the radiator cap
and open the drain cock at the bot-
tom of the radiator.
• Six Cylinder engine - remove the
drain plug located at the left side of
the block.
• Eight Cylinder engine - remove
plugs on each side of the block.
CAUTION: When
an
engine is
at
normal operating temperature or above, the internal pressure built up in the cooling system will blow
out scalding fluid and vapors il the radiator cap is suddenly removed. To prevent loss of coolant and to avoid the danger 01 being
burned, the coolant level should be checked or coolant added only when the engine is cool. To remove the cap when engine is cool,
slowly rotate cap counterclockwise
to
detent (DO NOT PRESS DOWN WHILE ROTATING) wait until any residual pressure is
relieved-as indicated by
a
hissing sound, then press down
on
the cap while continuing
to
rotate counterclockwise. Radiator
pressure caps should be checked by a qualified mechanic periodically lor proper operation and replaced as required with the
applicable AC type.
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