DIY - 12C Moldy Headlight Fix for less than 50.00 - McLaren Life
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post #1 of 28 Old 02-17-2017, 02:55 AM Thread Starter
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DIY - 12C Moldy Headlight Fix for less than 50.00

So I have officially completed this "DIY - 12C Moldy Headlight Fix for less than 50.00" twice, so now I'm officially the worlds foremost expert! OK, OK, that's a bit strong. At least I have a fair understanding of the process? Anyway, on to the How-To-Do-It part of the post....

If you own a 12C and you have swipe doors you either have already done this or you really-really need to do this. If you fall into the "need to" category then you are in for a treat because this is actually a pretty easy DIY that can be accomplished in one day. Make it a weekend project for a more leisurely pace.

Disclaimer - I'm sharing what has worked for me, and it's worked twice. I am not responsible if all does not go perfectly for you. I hope you find value in what I'm sharing, and if you do have success please share your experience with the community here on McLaren Life.

What you will need:

new - 1 very plush micro fiber tower 7.99
new - Meguiars PlastX plastic polish 8.99
new - 3M Headlight Restoration System (you only need the 3" foam pad piece) 22.00
new - Tube of black 100% silicone (not caulk) 4.99
new - (optional) 4 bags of Silica Gel desiccant moisture removal pouches
used - hand/cordless drill to spin the 3" foam pad
used - An assortment of flat tip screw drivers to pry the lenses apart

FYI - I bought these items NEW just for this task, because this was the BEST way to reduce the risk of dirt contamination that could have caused scratches inside the headlight lens. So DO NOT be tempted to use some old microfiber cloths or an old foam pad to save a few dollars, get news ones and make your life easier.

Step One - Remove the front bumper. (You can do this part for free, but I cheated because I'm a busy guy, so I paid my body shop buddy a hundred bucks to do that part for me). If your gonna do it yourself, first remove both front wheels, then unbolt the bumper top, bottom, and all around. Have a buddy around to help so you don't accidentally let it flip forward 90 degrees and scratch up that beautiful paint. Once the bumper is off you can now remove each headlight. you car will look like the orange one in the picture below. Be sure to take a picture or two with your smart phone because your friends will never believe you when tell them you did it yourself and who doesn't want to have cool bragging rights next time your having beers with the fellows?

Step Two - Pre-heat your wife's oven to 225 degrees and have a nice beer to relax as the oven warms up. You will need as many flat tip screw drivers as you can gather up, a nice number to have is at least 5. If you are a pro you can get by with just 1 or 2 but the more the better. Also get an old towel and lay it on the kitchen table so you don't scratch anything up as you work. Put one headlight at a time in the oven for 10 minutes exactly. don't mess that part up, (If you go longer I'm not sure exactly what happens... but my imagination tells me it ends in a big disappointment and a trip to ebay to find a new headlight). The heat will not hurt your headlight housing, but it will soften the black sticky stuff making it very easy to separate the upper and lower halves in Step Three.

Step Three - Using insulated pot-holders, remove the headlight and immediately pry the upper clear half off of the lower black half. Using one screw driver per little plastic tab, you can separate/pry open all the tabs simultaneously and then using one last screwdriver you can work you way around the entire housing and release/separate the two halves completely. If the headlight cools too much and the black sticky stuff gets cold then just pop the light back in the oven and repeat the process again. (TIP - if you have clear bra/stone chip protector film on your headlights just leave it on, it's tough and the trip thru the oven won't hurt it).

Step Four - repeat Step Three on the 2nd headlight.

Now its time to remove the ugly filthy scummy moldly looking stuff that has made its home inside your "billion-air doors" super cars headlight lenses!

Step Five - Apply the PlastX plastic polish to your foam pad mounted to your cordless drill. Using light pressure and medium speed to gently polish the entire inside of the lens. this step can be accomplished in less than 5 minutes per lens. Now use that brand new microfiber cloth to wipe off the excess polish and hold the lens up toward a light to inspect your work. Repeat the polishing as many times as needed until you are satisfied with the result. Once you are satisfied, be sure to clean out all the polishing compound (especially in the corners) before you reassemble both halves of the headlights.

Step Six - Stack the top lens on the black bottom headlight half and return them both to the oven for 10 minutes. Now that the black sticky stuff is soft again you can "press" both halves together and reattach all those little clips around the perimeter of the headlight housing.

Step Seven - Repeat step six for the 2nd headlight

(optional) - Once the headlight has been reassembled and has cooled down, insert one or two bags of silica Gel inside to create a super dry internal environment and to help prevent a repeat of the problem ever again.

Last step - You have to ask yourself, why did my headlights get all moldy in the first place? The answer is they were poorly sealed by the manufacturer. Our last step is to improve upon the original sealing by adding an extra layer of the black Silicone sealant all around the exterior where the two haves come together. Additionally my buddy Thad over at Hypercar development suggested the electrical plug connector is an entry point for moisture so please inspect yours and apply silicone as needed to prevent any water intrusion there as well.

If all went well you can now re-install both headlights, reattach your front bumper, bolt up those front wheels and take a victory lap around your neighborhood to show off those brand new looking headlights.

Job well done!
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- 2012 McLaren MP4-12C Graphite Gray (his)
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Last edited by ima2nr; 02-17-2017 at 09:02 PM.
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post #2 of 28 Old 02-17-2017, 03:34 AM
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People will pay big money to get that done!!
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post #3 of 28 Old 02-17-2017, 04:08 AM
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If it happens to me, can I send my lights to you?
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post #4 of 28 Old 02-17-2017, 11:39 AM Thread Starter
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Originally Posted by RonMathMD View Post
If it happens to me, can I send my lights to you?
Hi RonMathMD,

My true motivation was I really wanted to share how easy it is to fix your lights vs. just buying replacement headlights for thousands of dollars each. This is a very simple and "low tech" repair. I would suggest if you also used my "100.00 cheat" in Step One, then the same body shop technician that has the skills to remove and repair bumpers all day definitely has the skills to complete the entire procedure as well. I would believe you could show them this tutorial and then negotiate a fair price for less than or equal to the cost of shipping your lights to me, waiting on me, paying me, waiting on the shipping back, etc, etc. I would venture that 500.00 total would be very fair paid locally to your body shop guy for materials and labor to remove a bumper, cook your lights for 10 min each, polish away the ugly mold and then reassemble everything back good as new.

If someone still wanted to send me their lights I would say my price would be 350.00 to do the parts & labor not including shipping. Remember this is my "Go Away" price, but I guess if your willing to pay that much then I can drink a few beers on your dime and knock it out in an hour or so and have some extra gas money left over to go drive my McLaren 12C really hard for a few hours. CHEERS!
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- 2012 McLaren MP4-12C Graphite Gray (his)
- 2012 McLaren MP4-12C Brilliant White (hers)
- 2016 Tesla P85d w/Insane Mode

Last edited by ima2nr; 02-19-2017 at 12:48 PM.
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post #5 of 28 Old 02-17-2017, 12:02 PM
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I've always said that people should just crack them open and reseal them. They're just plastic headlamps. It's not like they are created in the vacuum off space and have to meet atomic level tolerances.

Crack em open.
Clean em.
Seal em.

End of story.
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post #6 of 28 Old 02-17-2017, 12:23 PM
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Thank You!!!!
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post #7 of 28 Old 02-17-2017, 01:11 PM
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I had a Toyota Supra back in the day which also commonly suffered from moldy headlights. This is exactly the process that everyone, including me, did to fix it. It really is pretty easy to do, so thanks for confirming that the same can be done on the 12c!
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post #8 of 28 Old 02-17-2017, 10:41 PM
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I was about to attempt this on my passenger side this weekend! I figured it's around $1500 to get a replacement off of ebay so why not try it myself first. As other people pointed out, it's just a headlight right? Thanks for the confidence builder!
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post #9 of 28 Old 02-17-2017, 10:47 PM
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post #10 of 28 Old 02-17-2017, 10:57 PM
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Fantastic! McLaren should still be doing this and come up with a permanent fix. That they don't bother really shows how much they don't give a darn about 12c owners. It's an embarrassment.
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post #11 of 28 Old 02-18-2017, 12:40 AM
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This is really very encouraging. Not so much the headlight fix per se, but it's good to see a body of knowledge building up within the McLaren community. It's exactly what Ferrari and Lambo owners enjoy, and is essential to the long-term viability of these cars. Long after the last 12c warranty expires this kind of fix is what will keep these cars on the road and enjoyed by their third, fourth and fifth owners.

Kudos ima2nr!
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post #12 of 28 Old 02-18-2017, 03:16 PM
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That must have taken some courage to do the first time - so thanks for figuring it out!

Great DIY work!


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post #13 of 28 Old 02-18-2017, 04:08 PM
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thanks for the diy
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post #14 of 28 Old 02-18-2017, 05:31 PM
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I'm in the process of doing this now. Took about 1.5 hours to take off the front bumper--most of that time is just trying to document all the different types of screws. Didn't need to remove the wheel well liners, just the front half of the screws. Broke some wire that was in the middle of the bumper holding some kind of antenna (wasn't in the documentation that i had so didn't see it). When it came to the headlight, took about 5 minutes to open. baked it, and used a putty scraper and didn't pry so much as pulled straight up on one of the lips of the clear plastic enough to get a finger under; then it's just a slow pull with a slight pry to the black plastic tabs to release the top. took a video while i was doing it, will clean it up to show how easy it was. one of the silica bags opened up in the headlight so now i have to clean all that up. Add a can of compressed air to the shopping list. more later.
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post #15 of 28 Old 02-18-2017, 09:10 PM
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Originally Posted by ZombiePhysicist View Post
Fantastic! McLaren should still be doing this and come up with a permanent fix. That they don't bother really shows how much they don't give a darn about 12c owners. It's an embarrassment.
To be fair, headlights are safety items and are therefore burdened by numerous regulations that make it difficult for McLaren to offer an officially supported fix.

Plus, the OP says he's already had to do this repair twice. That repair longevity is probably acceptable for a DIY job, but owners would be furious if a McLaren repair only lasted a year or two.

So, yeah, a permanent fix from McLaren would be very welcome. But the fact that they don't have one yet doesn't necessarily mean that they're indifferent to 12C owners.

Daily drivers:
1994 NSX - Brooklands Green with 300K+ miles
2012 12C - Racing Green with fewer miles (but still 3rd-highest USA, 13th-highest worldwide)
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