AFTER 30 MINUTES OF HIGHWAY DRIVING EXITED ONTO SECONDARY ROAD TO ADD OIL FOR LOW OIL LIGHT INDICATOR. ENGINE BEGAN SMOKING IN TWO MINUTES AND LIFTING HOOD CAUSED ENGINE TO BURST INTO FLAMES. CHEMICAL FIRE RETARDANT SPRAYED WITHIN THREE MINUTES. RESULT WAS INCINERATED ALTERNATOR AND ALL CODES ALARMED. CAR TURNS OVER. FUSES GOOD.