DURING RECENT WORK UNDER THE HOOD THE HOOD SUPPORT ROD (SUPPORT CYLINDER) BECAME NOISY AND RETARDED MOTION WHEN RAISING OR LOWERING THE HOOD. A SERIOUS ENGINE COMPARTMENT FIRE OCCURRED WHEN THE WHEN THE HOOD SUPPORT ROD BECAME DISENGAGED AT THE LOWER END SHORTING THE BATTERY TO THE ROD ATTACHED TO THE HOOD. THE VEHICLE WAS PARKED AND THE FIRE WAS OBSERVED UPON RETURNING TO THE VEHICLE FROM THE AUTO PARTS STORE..