including slipping in a check valve made by Nissan to keep it from dribbling. The valve cost about 7 bucks from Nissan, and I'm planning on getting it sorted this week. I'll report back the results.
this is the cause and the solution. but you do not need to buy the part from subaru or nissan. you can get one at the auto parts store and add it at almost any convenient place. i would try right at the wiper motor first. that is as easy to get to as any other location.
but i have never done it.