Buick RIVIERA 1993 Manual page 235

A
CAUTION:
Turning the radiator pressure cap when the
engine and radiator are hot can allow steam and
scalding liquids to blow out and burn you badly.
With the coolant recovery tank, you will almost
never have to add coolant at the radiator. Never
turn the radiator pressure cap
--
even a little
--
when the engine and radiator are hot.
Add coolant mix at the recovery tank, but be careful not
to spill it.
A
CAUTION:
You can be burned
if
you spill coolant on hot
engine parts. Coolant contains ethylene glycol,
and it will burn if the engine parts are hot
enough. Don't spill coolant on a hot engine.
Radiator Pressure Cap
When you replace your radiator pressure cap, an ACS
cap is recommended.
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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