0800 AM OWNER DROVE VEHICLE APPROX 6 MILES WITH HEATER ON, RETURNING HOME AND PARKING VEHICLE IN THE DRIVEWAY AND TURNING OFF ENGINE. OWNER EXITED THE VEHICLE AND ENTERED THE RESIDENCE. DRIVER NOTED A SMELL OF BURNING OIL DURING USE OF THE 6 MILE TRIP. APPROX 15 MINUTES LATER A NEIGHBOR ALERTED OWNER THAT VEHICLE WAS FULLY ENGULFED IN FLAMES. FIRE DEPARTMENT POINT OF ORIGIN INSPECTION STATES FIRE WAS IN INTERIOR UNDER DASH PANEL FIREWALL.