Thursday, October 1, 2020

McLaren MP4-12C: DIY fix of the dreaded "cloudy headlight"

As a reminder, I've had my McLaren MP4-12C for about 6 years now. It's a 2012 that I bought in 2014. It has about 55,000 miles on it now. 

If you own one or have been around a few 12Cs, you have likely seen or heard about one issue that has come up in a number of cars: the sealed headlights had a tendency to develop a condensation-like cloudiness on the inside of the plastic headlight covers. It's actually a kind of mold or bacteria that is not easily removed, so the typical fix is to replace the headlight.  Go to the dealership and a pair of new headlights will cost you several thousand dollars. Alternatively, you can generally find used  headlights on EBAY for about $500 -$800 each. Plus installation. My local dealership quoted me about $2400 to remove the headlights, recondition then, re-seal them, and re-install them. So, I decided to do it myself, and followed the repair advice of a number of members on the car forum MclarenLife.com. As it turned out, I did the whole job in a matter of hours over a day or two and with less than $10 of materials. I thought I would share it here in case it is helpful for anyone else.  

The first step is to get the car up a bit, so it is easier to get underneath the exterior panels to remove the bumper. So before we get to the fix, just a word about using my QuickJack BL-5000SLX on the McLaren. I've used my 5000SLX primarily for simple and easy access on my Cayman S and my Shelby GT350R. In both cases, it's a perfect fit. For the McLaren, the lift points are spread farther apart (front-back distance). So I needed to get the extenders from QuickJack.

By adding the SLX Frame Extension from Quickjack (https://www.quickjack.com/slx-frame-extensions/), the overall length of the lift rails is six inches greater, allowing the proper reach to the factory lift points (just barely!). The lift points are indicated underneath the car by colored circles.



But no good deed goes unpunished, and no purchase goes perfectly, either. Now that the lift is long enough, the added height of the adapter makes it impossible to slide the jack underneath the car. Mostly for the front, as the rear still has enough clearance. This photo below shows the new height (and length) of the lift with the extensions. I knew it would be close, as the website and docmumentation for the QuickJack is spot-on for their measurements, but I was hopeful I could slide this under.  As it turns out, I CAN do so, but then I have no room to insert the rubber blocks that go between the lift and the car's lift points.

So, I resorted to the simplest solution... drive the car onto a couple of "ramps" up front.  OK, maybe that is a grandiose label for a couple of 1"x6" blocks of wood, cut with a small angle on the leading edge.  In any case, by driving the car's front wheels up onto these block, the front end is now high enough to slide the jack underneath.  Add a couple of right-sized rubber lifting blocks that come with the Quickjack, and the car is up safely in minutes.


OK, so now that it was up, on to the somewhat laborious and intimidating job of tearing apart the headlights. There is no small about of trepidation associated with removing body parts off an exotic car, but in the end, it really isn't that much different than the old days when I was 17 and tearing apart my 1972 Datsun 510. Of course, back then, if it didn't go back together, who really cared?

Removing the front bumper consists of removing the fender liners and the plastic covers underneath the front splitter/skid plate. I found a number of helpful websites and YouTube videos, but in the end, there's a bit of hunting around for the next bolt to remove. Wish I had more photos for you, but my hands were kinda full and I was busy swearing at inanimate objects ;-). About 45 minutes later, I had the bumper off and laying peacefully on a tire.


There are a couple of headlight bolts that are hard to get to if you haven't pulled the fender liners off, but you can get to them. I hope you don't have chubby hands.





Headlights are off. Here is what they looked like. Note the milky condensation looking stuff that clouds the top third of the headlight. Yes, it would be great if you could just shove a Q-tip like swab in there to wipe it out, but it isn't just moisture. That stuff takes a lot of work to get off the plastic.




So here was the  weird part... it is now time to bake these babies at 200 degrees for about 10 minutes. In the oven. In your kitchen. Don't let your spouse or chef/foodie roommate catch you doing this. 


After time baking in the oven, the seal and rubber around the plastic becomes softer and pliable and you can then use a series of screwdrivers to (carefully!) work around the latch-tabs and the rubber to separate the headlight cover. This takes time, and time isn't your friend because the darn rubber sealant is hardening as it cools. I used a few more choice words at about this point, and questioned my own sanity.

But hey, it all came apart. Here are a few more close-ups of that mold.




At this point, I used a couple bottles of Meguiar's PlastX Plastic cleaner and polish and a pointed wheel polishing attachment on my high-speed drill.  I couldn't use my larger car buffer vert week because of the small areas being buffed. You have to get in those crevices, and this takes an hour or more for each headlight. After the first few passes with PlastX, I used a polishing compound to complete the refurbishment. When I was done, I baked it again to soften the rubber and reassembled the headlights, using black silicone sealant to augment the existing sealant material, which had taken a beating from my work.


Back together and looking pretty much as good as new!!


Of course, whenever you reassemble, there is ALWAYS that one extra part. Luckily, I knew exactly where it came from and it was only about a 10-minute detour to take the fnder liner back off and gee this little guy back where he belonged.


I managed to complete this all in maybe 4-5 hours total, not including couple trips to the store and a long explanation to my lovely wife as to why I was cooking car parts in the kitchen.


Back in business and rear for a little track day fun at Sonoma Raceway, but that's another story!