Erwin - Your post reminds me of days of yore - In the 60's we used to punch a hole on the back of a new muffler at the bottom in hopes of draining water out to extend the life of the muffler!

If I remember my molar chemistry correctly, (I got a C) the theoretical formula for burning a gallon of gasoline producer 22 gallons of water in the form of vapor.

BTW - your daughter is a good driver, looking under the car occasionally and being curious about what she finds. I also tought our daughters to smell at the car's grill when the car is hot occasionally to see if anything smells odd, such as antifreeze, oil, etc.