2005 Chevrolet Colorado Owner's Manual - Page 293

How to Check and Add Fluid The proper fluid should be added if the level does not reach the bottom of the diaphragm when it is in place in the reservoir. See the instructions on the reservoir cap. A 50/50 mixture of clean, drinkable water and DEX-COOL® coolant will: 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 5-28. 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. 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. 5-25