2007 Cadillac DTS Owner's Manual - Page 226

Engine Coolant Temperature Warning Light The engine coolant temperature warning light will come on when the engine is very hot. Engine Coolant Temperature Gage This gage shows the engine coolant temperature. This light will also come on briefly when the vehicle is started. If the light does not go out or comes on and stays on while driving, there may be a problem with the cooling system. Driving with engine coolant temperature light on could cause your vehicle to overheat, see Overheated Engine Protection Operating Mode on page 371. See Engine Overheating on page 369 and DIC Warnings and Messages on page 239 for more information. It can be used to see when your engine has warmed up and to make sure your cooling system is operating properly. If the gage pointer moves into the shaded area, the engine coolant is too hot and the engine coolant temperature warning light will come on. See Engine Overheating on page 369 for more information. 226