Crooks reportedly rent U-Haul trucks then, when the time comes to return the truck, top off the tank with water instead of gas, wrecking the engine...
Some scammers get away with it because the trucks are often handed over to the next customer very quickly. But water in the gas tank eventually brings the trucks to a sputtering stop.
"It can cost up to $2,000 each time it happens..."
Found at J-Walk, where a reader appended this comment:
I worked at an Avis rent-a-car when I was in college and we had similar problems; especially when the new model cars were bought from the car dealerships each year. The crooks would rent the cars for a day or two and then take to a chop-shop where they'd remove the brand new parts like carburetors, alternators, batteries, tires, mufflers etc. and then exchange for older parts that still functioned but were worn out.
Then the renter would bring the car back to the lot. Since the cars still functioned for a long time afterwards and then they were rented to others, the thefts would go unnoticed because there was no way to track who exactly was stealing the parts.