Yep ! Sounds very cool that you were able to do this. And 5 years of good use can't go wrong. Let me throw a little curve in the mix. Just a thought though. Many motors if not designed for it, create sparks from their brushes. I would think the windshield washer motors aren't built with suppression of these sparks.(though they could be, as they could throw out "radio interference" on your AM/FM radio or other componets in the car.) Maybe I am being to picky, could it be that you could ignite your "spilled" fuel from fueling operations while having the motor running?
Anyone else could chime in and help clear the air please would be appreciated.