Cadillac 2004 XLR - Manual (Page 252)

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 the proper level, add a 50/50
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. See
Engine Coolant on page 5-20
for more information.
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 coolant
surge tank pressure cap — even a little — they
can come out at high speed. Never turn the
cap when the cooling system, including the
coolant surge tank pressure cap, is hot. Wait
for the cooling system and coolant surge tank
pressure cap to cool if you ever have to turn
the pressure cap.
5-28