2007 Cadillac STS Owner's Manual - Page 396

Cooling System When you decide it is safe to lift the hood, this is what you will see: Some vehicles may have an engine driven fan, as well as the electric pusher fans which are located behind the vehicle's grille. {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. 3.6L V6 Engine shown, 4.6L V8 and 4.4L V8 STS-V Engines similar A. Engine Cooling Fans B. Coolant Surge Tank and Pressure Cap When the engine is cold, the coolant level should be at or slightly above 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. 396