Has anyone else experienced fine cracks in the side mirror light covers? It's happening on both sides. The cracks occur at the lip of the lexan cover, where the material is thinnest. I'm getting more of them throughout the summer. Hopefully, they won't extend past the gasket.

 

Yes, when I was car shopping for a new MB in May 2009, I noticed about 50% of the new C-Classes on the dealer lot had this problem (although most are very minor that you wouldn't notice it unless you were in bright sunlight and specifically looked for it... a few were very major and had major cracks all the way through the plastic).

I also checked out the pre-owned C-Classes, and about 80% of the used C-Classes with that same mirror design had some sort of cracking along the gasket lines (most were easily noticeable, like yours... some were very major as mentioned above).

It seems like this particular mirror design for the new C-Classes wasn't designed particularly well for this vehicle. The 2 most common "complaints" I've read about this mirror design is the "cracking clear plastic lens" issue (as you have mentioned), and the "excessive wind noise" which is caused by the "oversized" mirrors. The new mirror design supposedly solves these problems (or at least makes it less of an issue).

 

Its actually the lens separting from the body of the light...third brake lights are more common to have this. It is a vender issue I belive hella makes the lenses. This is a known problem dealer will cover it no problem..

Good luck

 

I haven't seen it on my car

 

Take it in to your dealer and have them fix it under warranty. Same thing happened to mine, but at first they said a rock had hit it. Next time I went in they said other MB's have had similar problems and fixed it under warranty

 

You can add a third common issue - moisture.

I think we have replaced around 20 of these lenses and all of them due to excessive moisture inside the housing.
Havnt noticed any cracking in them so I cant tell if that is the main cause..

 

Hmmmmmmmmm... that's a good point. I've heard about the moisture problem (although not as much as the other 2), but I attributed it to the cracked lens THEN moisture seeps in. If it's a totally separate issue, then that would not be good... one more thing for MB to "fix"...

 

I figured they had fixed the issue with these mirrors with the new 2009 model mirror, but oddly enough US-market still has the "old style" mirror on their 09.s

 

Yes, I've heard the new mirrors "fixes" these problems. I've also heard that the U.S. stayed with the same mirror style due to Mercedes wanting to use up their overstock before moving on to the newer one (same thing as to why the new 2010 E-Class still uses the older engines the 2009 models do, instead of the newer DI engines that will be used in the rest of the world).