Pontiac 2004 GTO - Manual (Page 223)

How to Add Coolant to the Coolant
Surge Tank
If you haven’t found a problem yet, check to see if
coolant is visible in the surge tank. If coolant is visible
but the coolant level isn’t at or above the COLD
FILL mark, add a 50/50 mixture of clean, drinkable
water and DEX-COOL
® coolant at the coolant surge
tank, but be sure the cooling system, including the
coolant surge tank pressure cap, is cool before you
do it.
If no coolant is visible in the surge tank, add coolant as
follows:
{ 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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