2003 GMC Sonoma Owner's Manual - Page 292

Checking Coolant Adding Coolant If you need more coolant, add the proper DEX-COOL@ coolant mixture at the coolant remvery tmk. Turning the radiator pressure cap when the engine and radiator are hot can allow steam and scalding liquids to blow out and burn you badly. With the coolant recovery tank, you will almost never have to add coolant at the radiator. Never turn the radiator pressure cap even a little-- when the engine and radiator are hot. -- The coolant recovery tank is located in the engine compartment near the passenger side of the vehicle. See Engine Compatfment Overview on page 5-12 for more information on location. The vehicle must be on a level surface. When your engine is cold, the coolant level should be at ADD, or a little higher. When your engine is warm, the level should be up to FULL HOT, or a little higher. 5-29