Date registered: Oct 2004
Vehicle: 2013 S550
Location: Tampa, Florida
Mentioned: 14 Post(s)
Quoted: 250 Post(s)
As I read this, it seems the most likely explanation (improper blade angle) isn't the case for your car.
In your case, when there is some drag on the blades, they don't chatter. Yet, when the drag is decreased by water, they do. To me, this suggests contaminants on the windshield. The blades are hitting small areas of contaminant (higher drag), then clean surface (low drag), then contaminant (repeating) - the contaminant often being oil or other road scum that isn't easily apparent in a thin layer. I had it start recently after installing brand new blades - which did fine for a short time, until I drove in heavy rain over roads having a lot of oily buildup after a long dry spell. The oil floated to the surface, and was splashed onto the windshield - and after a time, the blades started to chatter. I could see the traces of oily deposits at the upper corners, where the blades would chatter. You cannot see the deposits when the windshield is dry.
I have sometimes been successful getting rid of this junk by using Bon Ami cleansing powder - a non-abrasive cleaner made for use on fiberglass. It cleans without scratching, and it does a good job cleaning windshields. Use it liberally, but be sure to get it all off after using it. Get Bon Ami (or other low-abrasive powder made for cleaning fiberglass) at your local grocery store.
I used to experience this problem more when I used Rain-X - whether it was the old Rain-X itself, or whether junk bonded to the Rain-X, I don't know.
If that doesn't work, try twisting the blades as recommended - not just judging by looking at them.
2005 S500 4-Matic
Last edited by Skylaw; 08-09-2009 at 09:59 PM.