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Old 07-01-2008, 11:18 AM
HeyHomie HeyHomie is offline
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What Things Would Cause a Car to Catch on Fire?

Mammahomie traded in her 2002 Dodge Intrepid last Saturday. It had no known engine problems, though there was an issue with the transmission - it was fine at highway speeds, but below 30MPH it would "lurch forward" (Mom's words) from time to time, and she'd have to turn it off, then turn it back on again, and hope the problem didn't happen again.

The Monday after she traded in her old ride, she had to go back to the dealer to sign some piece of paperwork that had gotten lost in the shuffle, and the dealer told her by the way that the car had burned to the ground while one of the dealer's employees was driving it to a storage lot. The employee escaped uninjured, but the car was a total loss.

Any ideas as to what can cause a 2002 vehicle to burn to the ground (short of arson, wildfires, or obvious things like that)?
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Old 07-01-2008, 11:24 AM
Q.E.D. Q.E.D. is offline
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The thing that did in my 1982 Buick Skyhawk was a broken EGR component. Apparently, the metal corroded or fatigued and the EGR valve--which blows some of the HOT exhaust gas back into the intake manifold to improve efficiency--came loose and blew exhaust gas (did I mention it was HOT?) right on some plastic bit which melted and then caught fire. Once you have a fire in the engine compartment, the coating of grease, oil and road crap that accuulates in there feeds it quite nicely.
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Old 07-01-2008, 12:27 PM
SuperNelson SuperNelson is offline
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My brother's first MGB had an undiagnosed leak in the exhaust manifold gasket right below the side-draft carburetor. Eventually, this melted out the pressurized fuel line, and fuel sprayed on the exhaust. Once it ignited, the fuel pump kept running, adding fuel to the fire. Something shorted as it melted, and the fuel pump kept running at full power, even after the keys were removed. Eventually, someone from the fire department took a bolt cutter and cut the battery cable, disabling the entire electrical system.

The car was in the garage at the time the fire started. My 15 year old brother had the presence of mind to back the car out into the street as soon as he smelled smoke. And in the process, saved our house from burning down as well.
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Old 07-01-2008, 12:38 PM
brewha brewha is offline
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Quote:
Originally Posted by Q.E.D.
The thing that did in my 1982 Buick Skyhawk was a broken EGR component. Apparently, the metal corroded or fatigued and the EGR valve--which blows some of the HOT exhaust gas back into the intake manifold to improve efficiency--came loose and blew exhaust gas (did I mention it was HOT?) right on some plastic bit which melted and then caught fire. Once you have a fire in the engine compartment, the coating of grease, oil and road crap that accuulates in there feeds it quite nicely.
Holy Crap!

I came in here to report that my 1982 Buick Skylark met it's demise when it's engine caught fire. It had a slightly leaky valve cover and had accumulated sludge of oil/dust/debris on top of the engine. I had assumed that it had just ignited from the engine heat. I wonder if I had the same EGR component failure. Weird...
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Old 07-01-2008, 12:43 PM
Hilarity N. Suze Hilarity N. Suze is offline
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I have had TWO cars that caught fire. The first was the aptly named Triumph Spitfire (well, I guess Triumph was not too apt) and the reason was something to do with the carburetor and the fuel line. The second was a Pontiac ("we build excitement") Grand Prix, and the fire started in something electrical, melted something in the fuel line, and was fed by the fuel line and the grease etc. under the hood.

When the Pontiac caught fire I pulled over, popped the hood, saw flames, and started walking away. I thought, "Okay, by the time I'm half a block away no one will ever associate me with this car." Then a guy stepped out of an office building with a fire extinguisher and said, "Looks like you need this," and proceeded to extinguish the flame. A lot of people said how lucky I was to have this guy come right out with his fire extinguisher, but I think a truly lucky person wouldn't have a car that caught fire in the first place.
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Old 07-01-2008, 12:48 PM
masterofnone masterofnone is offline
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Back when I was in the Army, I had a HMMWV's fuel cell light on fire. The universal joint was throwing sparks on it for some reason, and the plastic lit on fire.
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Old 07-01-2008, 01:22 PM
Gary T Gary T is online now
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Early Triumph TR8's had their horn relays under the hood, "upside down." The open side of the relay casing faced upwards, with the electrical terminals protruding from the top. Somehow water was able to find its way into some of them, collecting in the relay which functioned as bowl. The water would eventually cause a short circuit between the hot and ground terminals, and from there it was like a typical electrical fire - the way-beyond-normal amperage caused the wire to get very hot, which melted and ignited its insulation.

My recollection is that several cars burned down while unattended, e.g. parked in a garage. I believe there was a recall campaign to reposition the relays, and of course the mounting procedure was changed on the assembly line.
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Old 07-01-2008, 01:26 PM
gotpasswords gotpasswords is offline
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Not tightening the oil filler cap after adding oil can cause hot oil to slosh out and hit even hotter exhaust manifolds. Also, a burst power steering hose can squirt hot steering fluid onto hot engine parts.

In both cases, we were able to extinguish the fire before it got unmanageable. I think that car secretly wanted to commit autocide.

My spouse had a car many years ago that caught on fire when a backfire ignited a nest that had been built in the air cleaner - once the flames were out, they found a mass of twigs and a cooked egg.
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  #9  
Old 07-01-2008, 01:44 PM
Gary T Gary T is online now
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Quote:
Originally Posted by gotpasswords
My spouse had a car many years ago that caught on fire when a backfire ignited a nest that had been built in the air cleaner - once the flames were out, they found a mass of twigs and a cooked egg.
Pardon my hijack, but that recalls a story...

I was working at a Fiat dealership and had just finished a pre-delivery inspection on a new car at closing time. The car stayed in my stall overnight, and the next morning the porter got in it to pull it out into the lot. It wouldn't start (cranked just fine).

I started checking it out. It had fuel, it had spark, but wait - why was the timing belt off a few teeth when it had run perfectly just the night before? I found out when I removed the timing belt cover and discovered a flattened corrugated mouse who had been pulled between the timing belt and one of its sprockets. Poor little thing just wanted a warm place to sleep.
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Old 07-01-2008, 02:06 PM
Throatwarbler Mangrove Throatwarbler Mangrove is offline
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Maybe the OP needs to rephrase the question as "What things would cause my non- British Leyland car with no Lucas electrical components to catch fire?".
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