The bonus symbol is the combination of the most popular tires on the petrol head, the steering wheel, the spark plug, the cowgirl and the fluffy scorpion. When the reel starts to spin, the game has a distinct mechanical feel.
The wildcard in this game is a wrench (or a transatlantic friend's wrench), and if you are lucky, it will appear at the right time as a substitute for another symbol and reward you.