Cadillac 2005 CTS - Manual (Page 312)

Cooling System
When you decide it is safe to lift the hood, here is what
you will see:
A. Coolant Surge Tank and Pressure Cap
B. Electric Engine Cooling Fans
{ CAUTION:
An electric engine cooling fan under the hood
can start up even when the engine is not
running and can injure you. Keep hands,
clothing and tools away from any underhood
electric fan.
If the coolant inside the coolant surge tank is boiling,
do not do anything else until it cools down. The vehicle
should be parked on a level surface.
If the engine is warm or hot, the coolant level should be
at or above the FULL COLD/FROID line on the side
of the coolant surge tank. If the engine is cold, the
coolant level should be near the FULL COLD/FROID
line on the side of the coolant surge tank. If it is not, you
may have a leak at the pressure cap or in the radiator
hoses, heater hoses, radiator, water pump or
somewhere else in the cooling system.
3.6L V6 engine shown, 2.8L V6 and
5.7L V8 engines similar
5-32