I personally don't see it working well for "car cleaning"
Auto is short for "automobile" which is very american or "automatic" I've never met anyone who calls they're car an automobile.
Professional valeting or detailing is a world apart from a car "cleaner" and is a bit of an insult to call either a cleaner, trust me :wink:
Automatic gearbox cleaner maybe? 
The first thing that came to my mind was one of those little vacuum cleaners that automatically hoovers your house while your out.