# Car mysteriously burns

**URL:** <https://boards.straightdope.com/t/car-mysteriously-burns/174374>\
**Category:** Factual Questions\
**Created:** [May 10, 2003, 8:07pm UTC](https://boards.straightdope.com/t/car-mysteriously-burns/174374 "2003-05-10T20:07:24Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![irish\_bill](https://avatars.discourse-cdn.com/v4/letter/i/ac91a4/32.png) [@irish\_bill](https://boards.straightdope.com/u/irish_bill)\
**Post date:** [May 10, 2003, 8:07pm UTC](https://boards.straightdope.com/t/car-mysteriously-burns/174374/1 "2003-05-10T20:07:24Z")

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Hi everyone,

Couple of nights ago, I was awakened by what sounded like a car horn being pressed. A loud bang later, I discovered that my neighbors car was on fire. The car subsequently burned out, and was a complete write-off. It was a late '90s fairly basic vehicle, I wouldn’t care to name the manufacturer, but they have a great rep… Are there any known causes for this happening? (except human endeavour, that is). Has it happened to any dopers?

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**Author:** ![UncleBill](https://avatars.discourse-cdn.com/v4/letter/u/d26b3c/32.png) [@UncleBill](https://boards.straightdope.com/u/UncleBill)\
**Post date:** [May 10, 2003, 8:19pm UTC](https://boards.straightdope.com/t/car-mysteriously-burns/174374/2 "2003-05-10T20:19:09Z")

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When I lived in Maine I saw smoke coming from the camper cover windows on my neighbor’s pickup. I pried open a window, and using a broomstick, pulled out the burning oily/greasy rags that had spontaneously combusted. The flames kicked up when I opened that window, of course, but there was no serious damage. I imagine the whole thing could have gone up eventually.

Funny thing after that, my lawn was always mysteriously mowed when I got home from work every Thursday evening (I usually mowed on Saturdays). Mainers are like that.

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**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\
**Post date:** [May 10, 2003, 8:23pm UTC](https://boards.straightdope.com/t/car-mysteriously-burns/174374/3 "2003-05-10T20:23:55Z")

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I had a car catch fire while it was running parked in the driveway years ago. Apparently part of the EGR valve corroded away, allowing hot exhaust gas to leak onto plastic parts. I got the fire put out, but not before it had done too much damage inside the engine compartment to be worth repairing.

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**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\
**Post date:** [May 10, 2003, 10:05pm UTC](https://boards.straightdope.com/t/car-mysteriously-burns/174374/4 "2003-05-10T22:05:09Z")

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Lots of possibilities. Among them, a relay that gets internally shorted, perhaps from water working into it. If it was the horn relay, that could explain both the horn sounding and the car burning.