A childhood belief about cars

my older sister loved to torment me when we were younger. when i was 3 or 4 she told me that if you leave the car running for too long it will explode. well, mom always ran short errands and left us in the car with it running. As soon as mom left the car to do whatever she did, my sister kim, would remind me about the car exploding. i would scream and cry and bang on the windows yelling that the car was going to explode and my sister would just have this devilish smile on her face. i learned about a year later it wasn't true when the poop truck came to pump out our septic tank, and of course, left his truck running. I was expecting the truck to explode at any minute. "Mommy, won't his truck explode?" she laughed and asked me where i heard that. so i told her. Boy, did kim get in a lot of trouble that night. hee hee hee