2002 GMC Envoy Owner's Manual - Page 341

Adding Coolant If you need more coolant, add the proper DEX-COOLR coolant mixture at the coolant recovery tank. CAUTION: You can be burned if you spill coolant on hot engine parts. Coolant contains ethylene glycol, and it will burn if the engine parts are hot enough. Don't spill coolant on a hot engine. Occasionally check the coolant level in the radiator. For information on how to add coolant to the radiator, see "Cooling System" in the Index. CAUTION: 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. Add coolant mixture at the recovery tank, but be careful not to spill it. Radiator Pressure Cap NOTICE: Your radiator cap is a 15 psi (105 kPa) pressure-type cap and must be tightly installed to prevent coolant loss and possible engine damage from overheating. See "Engine Compartment Overview" in the Index for information on location. 6-26