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So my 97 Subaru Legacy has pretty dim headlights, and it drives me up the wall. I like nice, thorough illumination when I'm driving at night; being able to see really does wonders for confidence on the road.

So I was at the mechanic today to get my loose power stealing belt tightened, and I asked him about it, and he took a look and said my lenses were all clouded over. Now, I was aware things were looking ancient up there, but I asked him a few more questions and he said that it would cost over $150 for new ones.

I believe him; he's a great mechanic. But can someone explain to me why the plastic cover over the headlight would be so damn expensive?

He said there'd be almost no point in getting new bulbs if the lens were blocking the light to begin with. This makes sense, but frankly I'm almost tempted to go ahead and just get new bulbs-- surely if they're bright enough they'll go through the cloudy lens? It's not that clouded. Am I wrong?

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Do they actually sell the lenses separately or would the whole fixture need replacing? Looks like the whole fixture for my car is easily $150 per light (mercedes not subaru). –  Ben Brocka Jun 2 '12 at 2:57
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4 Answers 4

up vote 5 down vote accepted

Unless the lenses themselves are badly damaged, I would try to polish them up first. You can buy kits with most of the necessary polishes etc from a lot of detailing supply companies- the one I have experience with is the Meguiar's kit that comes with plastic polish and a polishing "mop" for use in your drill. You'll also need a roll of blue painter's tape and I'd get some 1500 to 2000 grit wet'n'dry emery paper. Don't go any coarser than 1500.

Here's the way I restored plastic headlight lenses the last time I did it:

  • Generously tape up the paintwork around the headlights with the blue tape as you want to make sure you're not getting any of the abrasive polish or the sandpaper on the paintwork.
  • With the sandpaper used wet, carefully sand the surface of the lens. You basically want to get the worst of the UV damage and road rash off the lens before using the polish. Some lenses have a clearcoat on them that breaks down over time and sanding them removes the broken down clearcoat as well. Stop when the lens is a uniform colour and uniformly matte. Don't go nuts at this stage :).
  • Now use the polish to polish up the lens - it'll become clear again pretty quickly, but make sure it's uniform and that you don't leave any matte spots behind
  • Optionally, put a coat of good wax on the lenses for additional UV protection.

Polishing up the lenses will save you some cash over buying new lenses, but the downside is that you'll probably have to keep doing it once a year because they will cloud again. I'd take that over having to buy new lenses or light fixtures, though.

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The reason the lens clouds is that the lens is plastic and the UV rays from the sun cloud the lens'.Way back when, the government had a law that required the headlights to be standardized. Since the only lights available were sealed beam lamps the bulb,lens an reflector were changed when the bulb burned out. Since all cars used one of three lamps(hi beam,low beam or a hi-lo combination) they were cheap to manufacture.Some time in the eighties the law was changed to allow replaceable bulbs. Manufactuers could now design lights that were specific to each model. The result is because they are model/make specific they can be expensive.The good news is that because clouded headlights have become such a problem there is a fix. Go into any auto parts store and you will find a shelf full of polishes,cleaners and sealers to repair the lens'. Ask the counterman for a recommendation. They vary from polishers that fit on a drill to creams that require elbow grease. The prices range from $10 to $50.

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You could buy a pricey headlight lens cleaning kit, but believe it or not, for a quick fix, toothpaste works almost as well. Non-whitening, Baking soda based types are best. It's a good idea to wax them once you've polished them.

http://www.youtube.com/watch?v=CKAshYmrExc

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As an additional suggestion (though further from what you're asking), I find the lens polishing to be fighting an uphill battle. I do it 2-3 times a year in my Jetta, and I detest dim headlights.

HID conversion kits have really come down in price, and if you search eBay for a true HID kit (should come with bulbs and external ballasts, not just bulbs) then your headlights can be all sorts of foggy and you'll still have better visibility than clear normal ones. I was able to pick up a pair for $65 and wouldn't go back.

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You need to buy proper lenses, too. Installing the bulbs without proper lenses is a terrible idea. Yes; the road will seem brighter - but your light's throwing distance will be wrong and the cut off will be wrong so you're going to blind oncoming traffic and your high distance visibility is actually worsened. Please take care when converting to HID and do it proper. (Hint: It costs more than $60; I never found lenses for a 97 Caravan less than $120/lens.) –  Robbie Jun 8 '12 at 20:06
    
Thanks for the info; I didn't realize HID lights were supposed to be accompanied by lenses. The $65 above was bulbs and ballasts only. –  Ehryk Jun 8 '12 at 21:12
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