Cadillac 1995 Eldorado Owners Literature page 246

1. You can remove
the coolant surge
tank pressure cap
when the cooling
system, including
the coolant surge
tank pressure cap
and upper radiator
hose, is no longer
hot.
Turn the pressure cap slowly to the left until it first stops. (Don't press
down while turning the pressure cap.)
If you hear a hiss, wait for that to stop. A hiss means there is still some
pressure left.
2. Then keep turning
the cap, but now
push down as you
turn it. Remove
the pressure cap.
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