Hi everyone. I just finished up my Christmas break project of replacing my W211 headlight lenses and upgrading the original equipment xenon bulbs. I thought someone else might be interested in a few details. That plus I'm kinda proud of the result.

My car is a 2007 E350 and came equipped with both P1 and P2 packages, which is relatively rare. That included the xenon lights, but since I drive a lot in the pre-dawn hours on a rural highway I've been struggling to see. The original lenses had oxidized over time and grown quite cloudy, and I gather the xenon bulbs lose performance over time as well. Since I'm now up to 95k miles and ten years old it was time for the job.

Removal of the fender liners was straightforward on the driver's side but on the passenger's side in my car it was more difficult as there is a holder for some electrical wires toward the midline of the car. I couldn't see how to take this off without risking breaking the attachment, so I just undid the front portion of the fender liner. The underbody panel was simple. As to removing the bumper cover, I found that the toughest part was removing/reinstalling the side bracket that holds the side of the bumper cover to the fender above. Those babies were tight, and when I reinstalled them I found there was a hose (maybe for the headlight washers) interfering with lining up the part. I also found that somewhere along the way I lost one of the clips that acts as a nut to allow me to thread in an attachment bolt for the headlight unit. I worked around that with a little ingenuity and a trip to the hardware store.

One note for oem xenon: these headlights come with headlight washers, which I never use. What you'll discover is that there's a clip holding the headlight washer to the headlight lens, and this can easily be removed by undoing a silver Philips head screw and pulling the washer jet off. I didn't notice this on the first light I did and ended up breaking the clip.

For lens removal I used the oven baking method, so preheating to 200 degrees and baking for ten minutes. That works pretty well but on one headlight I had to put it back in for a few more minutes. If I had it to do again I'd buy a big tube of windshield sealant and use a caulking gun to lay down a nice thick bead. I've got my fingers crossed that I've got these well sealed, but if not that's how I'll do 'em over again.

For parts, I got the polycarbonate lens replacements on eBay for $40/pair, plus $10 shipping. Upgraded bulbs are Osram Night Breakers (the high end bulbs) from some online outfit, $148/pair. Installation is straightforward, but what is NOT straightforward is which bulbs fit the car. Many sites post WRONG bulbs for this car, so to set the record straight Mercedes W211 oem xenon lights take D1S bulbs for the 2007 model year (and I presume for later models as well). This despite seeing many websites telling me to get D2S, which would NOT have worked.

For instructions, there are several good YouTube videos. There are a couple of the ones that don't really show you the steps but there's also one by CarDOlogist that's pretty good on the subject, at least as far as taking the headlights out of the car. As to the baking method of lens removal, this is a pretty generic topic so most of the videos will be helpful. One tip I'd pass along is that the sealer used by MB comes off like warm bubble gum from a sidewalk, so you have to be careful not to let it get on the inner headlight's chrome. It won't come off easily, and if it does it can peel the chrome. I have a couple of little spots where that happened on mine but they're really not noticeable.

Pics are attached. Hope this info is helpful to someone else!

Wheels off, jackstands, fender liners/under body panel and bumper cover removed.


Original lens vs new lens.


Curing


New lens right/old lens left.


Result

 

Nice writeup and should be very helpful when I tackle mine in the coming months.
What's a good time allowance for this project - half a day?

 

Tough to say since I'm old and slow. I also didn't start on the job until about 1pm each day and quit when it got dark. Then there was the issue of somehow losing one of the little clips that act as a nut for one of the headlight mounting bolts, which meant an hour or so of looking for it. Not finding it meant a trip to the hardware store for a nut and washer, and then there was the matter of figuring out which mounting location to use the nut/bolt on (there's a reason they use those clips). You get the idea. At any rate, I was in a hurry to get the project done in a total of two full afternoons, and that was with what I fear may have been a sub-optimal job of re-sealing the headlights. We'll see next time I drive in the rain.

You'll probably be able to finish it up in half a day if you're quick to see how the bumper cover has to mate with the fender above and if you're careful to match up the proper overlapping of fender liner/underbody panel. Which I was not at first. A proper job would mean having some kind of solvent available to completely remove the original sealant, and then also enough new sealant to make a complete bead around the light's periphery. My plan going in was for the original sealant to still provide enough of a seal that it could just be augmented a bit by what I had on hand, and that's why I worry a bit about whether they're water tight.

 

Thanks.
Since I've never taken the bumper off or disassembled the headlights I better plan on a full 8 hours then.