Chevrolet 1993 Astro Passenger Owner's Manual page 265

Radiator Pressure
Cap
PO407
"wr radiator pressure cap is a 15 psi (1 05 kPa) pressure-type cap and
w s t be tightly installed to prevent coolant loss and possible engine
damage from overheating. Be sure the arrows on the pressure cap lir
with overflow tube on the radiator filler neck.
I
I
When you replace your radiator pressure cap,
u l ~
AC@ cap is IGdommendGu.
Thermostat
Engine coolant temperature is controlled by a thermostat in the engine coolant
system. The thermostat stops the flow of coolant through the radiator until the
coolant reaches a preset temperature.
When you replace your thermostat, an AC@ thermostat is recommended.
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