It is rather strange.
Next time they run off with the car door open
Well.. not sure where you live, but it is possible with some areas where there is a lot of hunting to literally buy fox urine (for trapping)
Maybe fill a small water baloon with some of that (smells very much bad) and throw it in his car ... or at it which ever.. wont do much good for his paint job LOL
Or ... sit some eggs outside, let him sit there good and long and wait for him
Umm he probably wont come back LOL
<evil grin>
HEY at least, I didn't tell him to put it in his radiator... (oh the lovely smell of turning on the heat that day

)