Well, you know that dashboard saint only work if your vehicle is Catholic; sometimes evangelical, but definitely NOT Jewish. You want REAL mechanical problems? Plant your St. Christopher on the dash of a Kosher Chevy.
Also, even if you've got a proper Catholic vehicle with a properly installed dashboard saint, you still have to freshen 'em up, once in awhile. Can't let the thing get all cracked and yellowed in the sun; it ain't respectful and will surely lead to problems.
I bought the truck from a Catholic, and he was kind enough to include a pewter saint. It seems to be in a constant state of prayer, so I'm not going to look a gift saint in the mouth. Besides: He said it was guaranteed for life.