2006 Hummer H2 Owner's Manual - Page 356

Checking Coolant The coolant surge tank is located in the engine compartment on the passenger's side of the vehicle. See Engine Compartment Overview on page 5-12 for more information on location. Adding Coolant If you need more coolant, add the proper DEX-COOL® coolant mixture at the surge tank, but only when the engine is cool. {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. When replacing the pressure cap, make sure it is hand-tight and fully seated. {CAUTION: Turning the surge tank pressure cap when the engine and radiator are hot can allow steam and scalding liquids to blow out and burn you badly. Never turn the surge tank pressure cap - even a little - when the engine and radiator are hot. The vehicle must be on a level surface. When your engine is cold, the coolant level should be at the FULL COLD mark. 5-26 Coolant Surge Tank 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. The coolant surge tank pressure cap must be fully installed on the coolant surge tank. See Engine Compartment Overview on page 5-12 for more information on location.