Headlight cover yellowing

[benchan]

Hi,

 

what do people do to prevent the headlight covers from gradually “yellowing” ? Is there anything I can apply?

My previous car’s (2012 GT86) headlight covers started looking yellowish after 8 years or so.

 

Ben

[Guest]

If you are feeling brave, try this to restore them before adding any lacquer or protection.

https://www.amazon.co.uk/3M-39008-Headlight-Restoration-System/dp/B001AIZ5HY/ref=sr_1_9?crid=376QCQ85FBQLV&dib=eyJ2IjoiMSJ9.t_KyMDLQdOiJttGtiRolI7plHhIdWBXVp33OfX7-3_nwdrLqL0CwuzPrV5TYHIXKQZ6Sko6gadb02OTqJv_kqCqJ4VpQzdwKRlm5MSv4NJZVS-ZjaGu4e0B85o3ut3-G0h-QDLTOVilQ8kI0UKNaI4E5CgksALT28r8scw8P78icWtlbpmauR52BV9tPpkv_M28VTrUQtmmkqQGOCK3igMbEYpe_e7aPKLEGr01C_MAb3vPnucGCEEpFpQZJJ4ZZhjso_9drpb51COOiz5w-IXZGwkCo4wxw5YtRVIHHmDA.RMtdSD4VmuDaRxhsevVYE8V60l6pjnYfj592YsSIROw&dib_tag=se&keywords=3m%2Bheadlight%2Brestoration%2Bkit&qid=1719136193&sprefix=3m%2Bheadlight%2Caps%2C81&sr=8-9&th=1

I had a birdy !Removed! on top of one unit, it "ate" (not the bird, the poopy) into the plastic. Although not on the front lens it did look unsightly.

I bought from an eBay seller and didn't pay Amazon's inflated price.

That 3m kit did the trick. There is a very useful Youtube video of it being used. I haven't followed up with any u.v. protection.

Why does that stupid filter accept poopy and not that without the y? Absolutely illogical and ridiculous! Must be set up by a 12 year old?

 

[ninanina]

5 hours ago, benchan said:

Hi,

 

what do people do to prevent the headlight covers from gradually “yellowing” ? Is there anything I can apply?

My previous car’s (2012 GT86) headlight covers started looking yellowish after 8 years or so.

 

Ben

I did my previous Prius headlights every year just before the MOT using a product called Peak.  It’s a kind of metal polish but works a treat for yellow headlights 

After I’d polished them with Peak I then applied any polish or wax I had to hand to seal them 

I did use to do them using a machine but found doing them by hand with Peak far easier and the end result was always amazing and it brings them up like brand new with not that much effort 

You could probably get away with using something like T-Cut or even toothpaste at a pinch but the best I ever used was Peak polish 

[Tommy X]

Try Toothpaste 

[ninanina]

7 minutes ago, Tommy X said:

Try Toothpaste 

Absolutely that will do if you have nothing else to hand

[Gren]

3 hours ago, Tommy X said:

Try Toothpaste 

Good suggestion, that worked well on my old car

[TonyHSD]

These headlights restoration kits works wonders but you need to use wipes or clear coat to protect the new shiny lenses. I did mine last year but didn’t use wipes and they have become yellow again. Will do them again this year and use the wipes with too coat,. 

[donkeychomp]

Fine grinding paste. Put it on like you would T Cut. Lasts about 3 months then you do it again. Toothpaste does work (it's that grinding effect) but doesn't last as long. Though spiders will give your lights a wide berth...

Alex

[Cyker]

The reason they yellow is they're made from polycarbonate plastic, which reacts with UV light over time and causes the yellowing.

Normally they are coated with something to block the UV, but it gets worn off over time.

You can polish off the clouded layer, but you really need to put the UV-blocking coat back on as soon as possible or the sun will started to make it yellow and it'll be even faster because there's nothing protecting the polycarbonate.

It's one reason all eye-glasses come with high-strength UV protection for 'free' nowadays - they don't  just do it for your benefit; It's to stop your specs going cloudy within a few months of daytime exposure because almost all the lenses are made of optical-grade polycarbonate!

[Paul john]

54 minutes ago, TonyHSD said:

These headlights restoration kits works wonders but you need to use wipes or clear coat to protect the new shiny lenses. I did mine last year but didn’t use wipes and they have become yellow again. Will do them again this year and use the wipes with too coat,. 

Surely its a chemical reaction with the uv over time. Therefore all you are doing is scraping off the top affected layer. 

[wildtapholer]

If it's really difficult to remove I use a fine wet and dry sand paper then buff with cutting compound like G3 then give a polish with a good car polish.

[Stevie J]

When I had the issue with my old 2006 Mk2 - it had really bad problems with fogging that started from the top of the lenses and then progressed further down the fronts, eventually putting it in danger of getting a big fat fail from Mr MOT tester.

I tried that Meguiars Plast RX stuff but it was useless to be honest - didnt work well at all.

In the end I sanded the lenses down with fine sandpaper, then cleaned them and sprayed them with clear lacquer. Seemed to be a better improvement than how they were before. The Mk2 2006 - 2008 seem to be the worst offenders for headlight fogging - Toyota used a really bad plastic on them that was badly affected by the sun. 

I've seen a few early Mk3's (2011 - 2015) now starting to be affected by the headlight fogging and yellowing, probably the ones never garaged and parked in the sun all day, which would accelerate the damage by the UV. The best option really would be to buy an aftermarket pair of headlights when the originals get so bad they just wont pass an MOT any more. 

[benchan]

Thanks guys.

 

So am I correct in saying that there isn't really a preventative solution other than to park the car out of direct sunlight or in the garage?

[bathtub tom]

Cling film, or perhaps a clear vinyl wrap. I believe it's UV light that causes yellowing, but don't know if either suggestion would limit the damage.

[TonyHSD]

No solution really, with the time any headlights will get yellowish.
Park away from direct sunlight, use soft cleaning agents , do not clean your lenses with cloth in between car washes , do not use any string chemicals on them to remove road dirt, insects etc , these are only steps to preserve your headlights for as long as possible. Once they start getting yellow, that’s it , you need to sand the yellow coat, polish and apply new top lacquer to protect from getting yellow again. 

[Cyker]

12 hours ago, benchan said:

Thanks guys.

 

So am I correct in saying that there isn't really a preventative solution other than to park the car out of direct sunlight or in the garage?

Well.. the solution is:

1) Polish out the yellowed parts

2) Apply a UV-protective coating.

Most of the fancier headlight restoration kits contain a UV-protectant.