I have this annoying problem with my windshield washer reservoir. Everytime i fill it up to the top, after about 3 or 4 days it will be empty. (No i dont use the windshield washer fluid). I changed the reservoir, and to no avail, it still drops to empty. I've checked the lines, and there doesnt seem to be any leak. No leaks on my garage floor in the morning of reservoir fluid. What can mysteriously drain my windshield washer fluid.

Agron
1989 300E (107k miles)