Cadillac CT4 2023 Owner's Manual page 302

If coolant is visible but the coolant level is
not at or above the indicated mark, add a
50/50 mixture of clean drinkable water and
DEX-COOL coolant.
Be sure the cooling system is cool before
this is done.
If no coolant is visible in the coolant surge
tank, add coolant as follows:
How to Add Coolant to the Coolant
Surge Tank
Warning
Spilling coolant on hot engine parts can
burn you. Coolant contains ethylene
glycol and it will burn if the engine parts
are hot enough.
Warning
Plain water, or other liquids such as
alcohol, can boil before the proper
coolant mixture will. With plain water or
the wrong mixture, the engine could get
too hot but there would not be an
overheat warning. The engine could catch
fire and you or others could be burned.
Warning
Steam and scalding liquids from a hot
cooling system are under pressure.
Turning the pressure cap, even a little,
can cause them to come out at high
speed and you could be burned. Never
turn the cap when the cooling system,
Warning (Continued)
including the pressure cap, is hot. Wait
for the cooling system and pressure cap
to cool.
Failure to follow the specific coolant fill
procedure could cause the engine to
overheat and could cause system
damage. If coolant is not visible in the
surge tank, contact your dealer.
If no problem is found, check to see if
coolant is visible in the coolant surge tank.
If coolant is visible but the coolant level is
not at or above the indicated 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.
(Continued)
Vehicle Care 301
Caution