2003 GMC Envoy Owner's Manual - Page 319

Engine Coolant The cooling system in your vehicle is filled with DEX-COOL@ engine coolant. This coolant is designed to remain inyour 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 5-27. 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. 0 Notice: When adding coolant, it is important that you use only DEX-COOL@ (silicate-free) coolant. If coolant other than DEX-COOL@ is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner at 30,000 miles -(50,000 km) or 24 months, whichever occurs first. Damage caused by the use of coolant other than DEX-COOL@ is not covered by your new vehicle warranty. What to Use Use a mixture of one-half clean, drinkable wafer and one-half DEX-COOL@ coolant which won't damage aluminum parts. If you use this coolant mixture, you don't need to add anything else. Let the warning lights and gages work as they should. 5-24