Cadillac 1993 Fleetwood Owners Literature page 247

A
CAUTION:
Steam and scalding liquids from a hot cooling system can blow
out and burn you badly. They are under pressure, and if you
turn the radiator pressure cap
--
even a little
--
they can come
out at high speed. Never turn the cap when the cooling system,
including the radiator pressure cap, is hot. Wait for the cooling
system and radiator pressure cap to cool if you ever have to turn
the pressure cap.
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