1999 Pontiac Grand Am Case Study Origin and Propagation

Fire originated near the rear of the engine, low in the engine compartment and somewhat toward the right side. The burn pattern on the hood and behind the engine confirmed this. Fire spread upward in the engine compartment and remained high. The discoloration on the underside of the shielded rear exhaust manifold was concentrated on the passenger side only. Fire was extinguished prior to entry into the passenger compartment. The windshield showed heat damage but no breach.

Hood folded in half during salvage. Burn pattern toward rear, which is on left side in photo.

Power steering lines and fittings were in close proximity to the shielded exhaust manifold and to the center of the burn pattern. Although higher on the engine, gasoline and coolant lines were located within the heat damaged area as well and could not be eliminated as possible sources of originating fuel. Given the driver’s observations of steering system malfunction just prior to seeing gray smoke, it was concluded that most likely the fire originated due to a power steering fluid leak ignited on the exhaust manifold.

Engine compartment, with bulkhead toward right in photo. Fire is believed to have originated on rear of engine, near bulkhead, low in engine compartment.

Smoke and heat damage on inside of windshield and on dash cover. Fire had just begun to propagate to interior when it was extinguished.