Why does white smoke come out in a hummer h2?

White smoke coming from a Hummer H2 typically indicates that coolant is entering the engine's combustion chamber, which can suggest a blown head gasket, a cracked engine block, or a damaged cylinder head. This can lead to overheating and significant engine damage if not addressed. It's essential to diagnose the issue promptly by checking coolant levels, inspecting for leaks, and conducting a compression test. Continuing to drive the vehicle in this condition can exacerbate the problem.