GMC 1996 Sierra Owner's Manual page 231

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 hat engine.
When the coolant i n the coolant recovery tank is at or
above
the
COLD mark, start your vehicle.
If the overheat warning continues. there's one more
thing you can try. You can add the proper coolant
mix
directly to the radiator, but be sure the cooling system is
cool before you do it.