2004 GMC Envoy Owner's Manual - Page 335

Add coolant mixture at the recovery tank, but be careful not to spill it. Radiator Pressure Cap Notice: If the pressure cap is not tightly installed, coolant loss and possible engine damage may occur. Be sure the cap is properly and tightly secured. See Engine Compartment Overview on page 5-12 for information on location. {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. Do not 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 on page 5-30. 5-27