Chevrolet 1994 Blazer Owner's Manual page 261

Add coolant mix at the recovery tank, but be careful not to spill it.
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.
When you replace
your radiator pressure
cap, an A P cap is
recommended. See
"Service Replacement
Part and Filter
Recommendations" in
the Index.
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