ENGINE BAY CAUGHT FIRE AND CAR IS A TOTAL LOSS. ENGINE HAD BEEN REPLACED PREVIOUSLY UNDER SONATA THETA ENGINE RECALL. INDEPENDENT MECHANIC NOTICED THAT THERE WAS A FUEL LEAK IN THE ENGINE BAY. WAS ON THE WAY TO HYUNDAI DEALER WHEN THE FIRE HAPPENED. THE CAR WAS MOVING AT ABOUT 20 MPH WHEN IT LOST POWER AND SMOKE STARTED SPEWING FROM UNDER THE HOOD. EXITED THE VEHICLE AND THE ENGINE BAY WAS ABLAZE WITH 60 SECONDS. NO INJURIES OCCURRED.