A friend pointed out to me on his Boxster that he has a oil leak of some kind, but in a very strange place for oil to appear. He showed me the black fluid streaks at the bottom of the front quarter panel, between the door and the wheel well opening, and it runs down to the bottom of the rocker panel. But he says it never extends backward onto the door and it never extends beyond the door-quarter panel gap. The rest of the car is almost spotless, always. He asked what is it. If he was driving thru water puddles, he would have messy splashing on the lower half of the car going every which way, not just in the one area. I told him that it is not a system leak. I could not help him beyond that except to say that my 911 does exactly the same thing. So where is this fluid coming from, and why on a car going 60 mph does this fluid not get blown further back along the car? Is this some kind of condensation draining that is happening at night as the car cools down in the garage?

 

I used to get the same streaks on my 718BS found it came from the over flow of the windshield washer reservoir. Living in Arizona I never filled it my self, but the dealer would and it would streak like that, it would stop as the level in the container went down. By this time I was due service again, they would fill it and the streaks came back. The more spirited you drive and slosh the liquid in the container the more streaks. All the road grime behind the left front tire wheel well mixes with the clean liquid and results in the black streaks. I never figured out a way to keep it from streaking, I just carried detail spray and a rag for a quick wipe!

 

CaptLeslie,
I jacked up the front end, took the wheel off, & removed the wheel well liner, & found the washer fluid tank exactly as you explained it. Thanks for the information.