DRIVING VEHICLE ON DIRT ROAD, ROAD ABRUPTLY TURNED TO SOFT SAND. VEHICLE WAS LAGGING IN THE SAND. ABLE TO GET VEHICLE TURNED AROUND TO GET BACK TO SOLID ROAD. SWITCHING BETWEEN AUTOMATIC & MANUAL MODE ON THE TRANSMISSION TO KEEP MOVING FORWARD. AFTER VEHICLE WAS TURNED AROUND, SMELLED SOMETHING BURNING & SAW SMOKE FROM UNDER HOOD. STOPPED VEHICLE TO LOOK UNDER HOOD. UNDER HOOD SMOKE COMING FROM DOWN BELOW ENGINE AREA ON FRONT DRIVERS SIDE AREA. SMOKE WAS THICK WHITE & CHEMICAL SMELLING. ENGINE AREA IGNITED TO FLAMES. ATTEMPTED TO PUT FIRE OUT WITH WATER WITH NO LUCK. VEHICLE COMPLETELY BURNED UP. VEHICLE WAS A RENTAL CAR. *TR