Radiator Pressure Cap - GMC 1996 Sonoma Owner's Manual

Radiator Pressure Cap
NOTICE:
Your radiator cap is a 15 psi (105 kPa)
pressure-type cap and must be tightly installed to
prevent coolant loss and possible engine damage
from overheating. Be sure the arrows on the cap
line up with the overflow tube on the radiator
filler neck.
Thermostat
Engine coolant temperature is controlled by a thermostat
in the engine coolant system. The thermostat stops the
tlow of coolant through the radiator until the coolant
reaches a preset temperature.
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