The mysterious auto fire

Mar 1, 2006 by

The call came in that there had been a vehicle fire of unknown origin-would we check it out?

Our story begins with the kids telling Dad that there was smoke in the garage.   He then ran out to the garage, where their two-year old car was parked, and while it was not in flames, it was smoking dramatically.

He then quickly pushed the car into the driveway, which sloped down to the street.

The car rolled into the street and then rolled back to the curb due to the crown of the road.   Fortunately, no one was struck and no property was damaged.  The smoke then cleared, and the fire apparently self extinguished.   As the smoke dissipated, it left no trace.   As he looked the car over, he could not tell what had burned.  The engine compartment looked ok, the seats, windows and headliner looked ok.   The car started normally, and the engine sounded normal.

Still unnerved by the experience, the insured felt the dealer should do something, since the car was still under warrantee.   He then had the car towed to the local Chevy dealer and reported the problem to his insurance company.   At that point GEI was called to investigate.   This is where the story gets a little confusing.   The dealer gave the car the once over and announced, “no fire, no problem”.   For unknown reasons, someone called a local repair shop to come pick up the car.   The repair shop sent over one of their guys, who then drove it to their shop.

The repair shop then called the insured to come pick up the reportedly normal car.   The insured arrived at the repair shop at the same time as our expert arrived to inspect the car.   Since he was already there, they decided to let him inspect the car while the insured paid for the various services that had been rendered (!!!).

As an aside, the repair shop driver commented to our expert that the brakes were real soft.   Now our expert had been sent out for a fire inspection, so he thought that someone in the office had mixed up a fire inspection case with a brake inspection case.

He began his inspection.   The interior appeared as a two year old interior should look, with no fire or smoke damage.   The engine and transmission were unremarkable.   The electrical fuses were all normal.

He performed a brake pedal test with the engine off and discovered that the pedal was low.   Further investigation showed that while the brake booster reservoir was full, the master brake cylinder fluid reservoir had an empty front chamber and a nearly empty rear chamber.   When our expert energized the electrical system, the dashboard brake warning light came on and remained on after starting the car.   So where did that fluid go?

Inspection of the four wheels showed no signs of leakage from any of the four brakes.   The undercarriage had the beginning of leaking fluid drip marks on it.   Our expert then traced the brake lines from the master brake cylinder to the wheels.

He found the answer near the ABS control unit located on the belly pan, roughly under the driver’s seat area.   Wires to the ABS system plug had been looped over one of the brake lines going to the rear axle, instead of being routed in their proper channel.   In two years of driving, the wires had chaffed and worn through their insulation.  They then shorted to the ground provided by the brake line.   This created a miniature arc welder that burned a pin hole through the steel brake line.   The brake fluid then started leaking, and when heated by the red-hot shorted wires, started to smoke and burn as well as melting the small nearby plastic pieces.

The car had two near catastrophic conditions.

First, the car was close to total brake failure due to the fluid loss.   It would have taken just a few more miles and brake applications until air would have entered the lines and the brakes would have failed completely.

Secondly, the car was dangerously close to burning again.   If the owner or shop had added more brake fluid and continued to drive it, more brake fluid would have been pumped onto the bottom of the belly pan, where it would have coated the undercarriage from the leaking line to the rear of the car.   The fire went out earlier for lack of fuel.   A covering of brake fluid over the whole back of the car would have provided a path for the fire to travel to the numerous plastic and rubber fittings in the rear of the car including the plastic connectors of the gas lines.   Had those gas line connectors melted, there would have been a fire that would have consumed the entire car.

It is safe to say that our expert’s inspection, observations, and conclusions prevented both a crash due to loss of brakes and a disastrous fire of the two year-old vehicle.

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