Auto Maintenance: Mr. Green Car: Seeing the light: Repairing cloudy headlights

May 16, 2012

On the left — dull, cloudy headlight lens. On the right — a lens after the cleaning procedure with sandpaper and finish polish. (Photo by Allen Penticoff)

By Allen Penticoff
Free-lance Writer

I had, in recent days, been pondering getting a new or late-model used car. There are many nice ones to choose from, but in the end, my wife and I decided to keep our old car and instead spend our money on travel. We have a “bucket list” of places we wish to travel to, and it’s an either/or situation based on cost. New car OR travel. Travel won.

To keep our old cars looking good, and consequently in condition that makes them proud to own and serviceable, I’ll offer a couple of tips that are very inexpensive but very beneficial to the life of your car or truck in future columns — beginning with repairing cloudy headlights

Except on a few much older vehicles with “sealed beam” headlights where you replace the whole light assembly when they burn out — modern vehicles have a headlight assembly with replaceable halogen light bulbs. This is usually an easy do-it-yourself job if you do have a light burn out. Just be sure not to handle the glass on the bulb, as the high temperature and the oil on your fingers can shorten the life of the bulb. The problem that really arises is that over time, some of the lenses become very dull and cloud up. They look bad, all yellow and opaque — and the light does not shine through very well. This reduces the distance one can illuminate the road at night — a safety issue.

Fortunately, there is a fix that does not involve replacement of the expensive headlight assembly. The lenses can be polished back to their original clear state. There are two ways to go about it. One way is to use an electric buffing machine and various degrees of polishing compounds. This works fast, but one needs a good buffer to do this. Body and detail shops have this equipment, and will, of course, charge appropriately for their time.

The second way involves a little of your money and some of your time. This is to use several different grades of WET OR DRY sandpaper and some polish. You will need a bucket of water, something to sit on, sandpaper, polish and some clean cloth towels or good soft paper towels. Auto parts stores sell kits for polishing headlights — but I’ve noted that these kits are quite expensive considering what little they contain. You can assemble the same stuff for much less with a trip to a hardware store or auto paint supply store.

You will need: 1 sheet of 120 grit WET OR DRY sandpaper, 1 sheet of 320 grit WET OR DRY sandpaper, and 1 sheet of 600 grit WET OR DRY sandpaper and a bottle of finishing polishing compound such as 3M’s One Step Cleaner and Wax or Maguire’s Mirror Glaze. You can also buy the “plastic cleaner” products both manufacturers sell. 3M sells a Lens Polish and Protector, too, but it may be harder to find. Both claim the use of the cleaner and polish together will clear your headlight lenses — but at the same time sell the kits with all the sandpaper needed, too. Sandpaper may come in five-packs — try to find some place to buy just one sheet, because that’s all you’ll need. Do not use ordinary dry sandpaper on plastic lenses.

I’ll assume your headlights are in really sad shape. If not, you can skip right to using the polish. First, with a bucket half-filled with water (warm makes it more pleasant to do). Fold and tear the sandpaper into quarter sheets to make a manageable size. Fold the quarter again. Now, dip the 120-grit paper in the water and begin to sand on the surface of the lenses. As the sandpaper fills with plastic grit, swish it around in the bucket to remove the grit. Keep the paper wet. Each time you completely sand the surface of the lens, wipe with a damp towel to remove the grit. It will take a lot of sanding with the 120-grit to get down to the good plastic. Repeat with the 320-grit paper, then the 600-grit paper. It will look like you are making things worse at first, but as you work your way up through the finer grades of sandpaper, the lenses will begin to clear up as you make finer and finer scratches.

After thoroughly washing the lenses with fresh water and drying them with a clean towel, it is time for the polish. Using a soft towel or applicator, polish, polish, polish the surface. Wipe and buff off the haze with a soft towel each time you have finished a small area (old diapers work great). It will take several repeats to get a crystal clear lens. Step back and admire your work. Your car or truck will look like new! Now, don’t let them get so bad that it takes all that work (about an hour). Clean the lenses regularly with plastic cleaner and polishing a bit, and it will be much easier to keep them looking great.

From the May 16-22, 2012, issue

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