2005 Cadillac STS Owner's Manual - Page 313

If you do not use your vehicle under any of these conditions, the fluid and filter do not require changing. Notice: Use of automatic transmission fluid labeled other than DEXRON®-III, Approved for the H-Specification, may damage your vehicle, and the damages may not be covered by your warranty. Always use automatic transmission fluid labeled DEXRON®-III, Approved for the H-Specification. A 50/50 mixture of clean, drinkable water and DEX-COOL® coolant will: Give freezing protection down to −34°F (−37°C). Give boiling protection up to 265°F (129°C). Protect against rust and corrosion. Help keep the proper engine temperature. Let the warning lights and gages work as they should. Engine Coolant The cooling system in your vehicle is filled with DEX-COOL® engine coolant. This coolant is designed to remain in your vehicle for 5 years or 150,000 miles (240 000 km), whichever occurs first, if you add only DEX-COOL® extended life coolant. The following explains your cooling system and how to add coolant when it is low. If you have a problem with engine overheating, see Engine Overheating on page 5-26. Notice: Using coolant other than DEX-COOL® may cause premature engine, heater core or radiator corrosion. In addition, the engine coolant may require changing sooner, at 30,000 miles (50 000 km) or 24 months, whichever occurs first. Any repairs would not be covered by your warranty. Always use DEX-COOL® (silicate-free) coolant in your vehicle. 5-23