 I bought a brand new Sienna. My wife drove the car with my mother in the passenger seat when we left the dealership. After half an hour, when my wife turned the heater on, the engine started making loud thumping sounds. My mother noticed a glow in the hood. A considerable amount of thick dark smoke started rising from the hood. My wife stopped the car immediately and turned the engine off. Thinking that the engine was about to explode, they leaped out of the car and ran away to a safe distance. The car kept emitting smoke for 30 minutes. Toyota could not diagnose the reason for the problem. Still, it insists that I take this dangerous car back.