UPON EXITING FREEWAY I NOTICED A BURNING ODOR. PARKED THE SURBURBAN AND LIFTED THE HOOD AND DISCOVERED THE LEFT FRONT AREA OF ENGINE ON FIRE. I EXTINGUISHED THE FLAME AND THE RESULTING DAMAGE EXHIBITED SPARK PLUG WIRES 1 AND 3 TOTALLY BURNT TO ASH. WIRE HARNESS TO AIR CONDITIONING AND ENGINE TEMPERATURE SENSOR INSULATION WAS BURNT AWAY. OIL FILLER NECK IS COMPLETLY MELTED AWAY AS ARE THE SPARKPLUG WIRE MOUNTING BRACKETS. PLASTIC VACCUUM HOSE FOR EMMISSION DEVICE WAS ALSO MELTED IN HALF. UPPER RADIATOR HOSE IS BADLY BURNT. SUSPECT ELECTRICAL WIRE HARNESS PROBLEM WITH VEHICLE SINCE THE BATTERY SPLIT OPEN 1 YEAR PRIOR SPILLING ACID ALL OVER BRAKE LINES AND AIR CONDITIONER PLUMBING. *AK