2004 Buick Rendezvous Owner's Manual - Page 347

The vehicle must be on a level surface. When your engine is cold, the coolant level should be at the FULL COLD mark, or a little higher. When your engine is warm, the level should be above the FULL COLD mark or a little higher. {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 on page 5-29. Adding Coolant If you need more coolant, add the proper DEX-COOL® coolant mixture at the coolant recovery tank. {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: The radiator cap on your vehicle is a pressure-type cap and must be tightly installed to prevent coolant loss and possible engine damage from overheating. Be sure the arrows on the cap line up with the overflow tube on the radiator filler neck. The radiator pressure cap is located at the front of the engine compartment on the passenger's side of the vehicle. See Engine Compartment Overview on page 5-12 for more information on location. 5-25