Overhaulin'

The show's premise was that an unknowing "victim" – the mark, in the show's language — is nominated to be "Overhauled" by their family or friends, the insiders Their car, usually an old and tired antique car was obtained through some ruse. Some common examples included the car being "stolen" by Chris and Chip, a car being misplaced or lost at a mechanic's shop, or the car being towed away by "police".

Source: Wikipedia.org