I've had this 2003 W210 wagon for nearly a year and in most ways it's perfect. The worst thing about it is its seeming inability to clean the windshield. I live in Portland, so this is a big deal

The problem is streaking, and it's usually worse on the forward stroke than the back. It seems like there are areas where the blade touches the windshield going one way but not the other. Driving at night in the rain is a little terrifying.

The blade was new when I got the car, and I got another new blade a few months ago, to no effect. The windshield itself is in perfect condition. I've been using Wurth "Rapid Windshield Cleaner" concentrate that MBI gives me.

I've used RainX washer fluid before with excellent results. From what I've read here, the alcohol in RainX gets rapidly evaporated by the washer fluid heater in this car, so I've not tried it.

I've not tried what might seem obvious: RainX the windshield directly. It grates on my nerves to even think about it: the wipers on the SDL were magical, even with cheap-ass fluid.

Any advice?

__________________
2003 E320 wagon, ~80k, "Sputnik"
1987 300 SDL, ~160k, "The Pimp Daddy" (sold April 2010)
1984 300 TD, ~200k, "Das Boot" (Demised March 2008)