Fixing cloudy, fogged, or pitted headlights
Over time, plastic headlamp lenses often become yellow, cloudy, and pitted. While manufacturers have moved to more durable anti-UV coatings, many drivers of older cars are faced with ineffectual headlights because the cloudy lenses absorb the light instead of passing it through.
If your headlights are still only mildly cloudy, use the least aggressive approach you can, such as Meguiar's Body Scrub or TR3 blue-label car polish; that will preserve some of the factory protective coating. If they look like the ones in the picture above or resist the gentle approach, keep reading.
“beans,” using information from the Allpar forums, suggested:
- Wet sand with 600 grit sandpaper until the surface is smooth.
- Wet sand with 800 grit and then 1000 grit sandpaper.
- Polishing begins with 1200 grit wet sandpaper.
- Buff out with very light cutting compound (e.g. Meguir’s #2 swirl remover).
- Finish polishing with a good plastic polish (e.g. PlastiX).
He used an electric buffer for around 20 seconds with the swirl remover on each light, followed by hand buffing. Gloves are recommended for the wet sanding.
Numerous people confirmed their success in making terrible-looking, almost useless headlight lenses look brand new. A variety of kits are sold, mainly using sandpaper or electric drill disks with adhesive foam pads. Individual sheets of sandpaper are available from well stocked auto supply stores, with highly variable pricing — they might exceed the cost of a kit.
Allpar trial #1: sandpaper plus PlastiX
We tried one method on the left headlights, another on the right headlights.
On the first headlight, we started with 800 grit, which added considerable time to the process — our headlights were bad enough to merit starting with 600 grit. We went to 1000 next, then PlastX; we recommend using the 1200 sandpaper between them. In all cases we wet-sanded.
You can't see what you're doing because the headlight is covered under a milky coating of loose polycarbonate, unless you've got a constant stream of water going. Be thorough and get all areas of the headlight. It took us around ten minutes working by hand on a 300M headlight to get most of the effects of aging off, with the most coarse sandpaper, but we later went back and did it again for a more thorough job.
Next, we get rid of the pits and scratches introduced by the 800 sandpaper by using the finer grades, gently and thoroughly. Don’t be shocked when you've finished with the 1000 grit sandpaper and your headlight now looks like it's a frosted shower window. As it dries, it will look worse.
Finally, use the PlastiX as indicated - unless you've noticed an area you want to hit with the 600 grit again, and then go up through each step until the PlastiX. You don’t want to start over, and PlastiX is expensive. Based on our experience, I’d suggest spending more time, rather than less, on that first step, because we had to go back and do it again. You can barely see the fog on the bottom of the headlights; and they are still somewhat cloudy in the following photo.
When you’re done, it should look much better. Still, the hazing slowly started to return within a few months, and we did not manage to get the surface as perfectly smooth as we'd have liked. That led us to the second trial:
Allpar trial #2: The DoubleHorn headlight restoration kit
Daniel Stern, automotive lighting expert of worldwide repute, recommended that we try the $30 (including shipping) DoubleHorn headlight restoration kit, saying it was the only kit worth the bother. We called DoubleHorn and quickly got a headlight kit (along with a metal kit for restored cars that we will test, um, when we figure out what to do with it.)
The DoubleHorn kit comes with a generous amount of each of its materials, which a reasonably talented person could probably stretch out to three cars. The 3M pad showed little wear (though we did get the rough side dirty when using the fine side), and was much easier to use than sandpaper. All materials were biodegradable, the protective coating met California requirements, and the box was no larger than needed (with useful compartments for long-term storage).
For cars with very bad headlights, you could spend hours and hours using their mildly abrasive pad and cleaner. They will work, but be very time consuming on cars with headlights that are very far gone, like ours were — just a year after the sandpaper alone. In these cases, start out with the 600 sandpaper, then move to the 800, then move to the DoubleHorn cleaner, then the PlastiX, then the DoubleHorn final fine polish, then the sealant. (The PlastiX worked much faster than the DoubleHorn Micro Abrasive Gel, in our experience.)
Once the headlights are nice and smooth, the DoubleHorn spray is forgiving and easy to apply. Mask off the surrounding area (we quickly stuck and unstuck 3M masking tape to our pants leg to make it even less sticky), spray one thick coat, and step back to enjoy it. We had two runs on our first spray but they both dissipated quickly and disappeared on their own; the headlight looked like it was covered in gel for around 20 minutes, then dried to a shiny, clear finish, looking brand new. The DoubleHorn sealant is supposed to replace the original factory UV protection. However, after a year, the headlights did not look nearly as good; they still did not degrade nearly as much as they would have without the sealant (one year after using just the sandpaper and PlastX, the headlights looked about as they did after ten years out-of-doors, because the sandpaper takes off the factory UV protection).
The light should be going through the lens, not sticking to it. The sealant seems to take care of some minor “glitches,” filling them in with a smooth surface. The difference is striking, and we don’t know if other kits have the same qualities. (Compare the photo below with the “after” photo above.) Perhaps the trick is to apply multiple coats of the sealant, and to refresh it from time to time.
The DoubleHorn kits — and other relatively non-intrusive methods described here — are also good for sidelights, tail lights, and any other lenses, which may be more helpful for those with vintage cars than modern vehicle owners.
Some may ask why they can't just use DoubleHorn’s sealant. A can of the resin sealant is available, cheaply, from the company - at $9.95. However, you have to have a $10 order to check out, and then shipping adds around $12 more, and you end up paying about as much as you would for the kit, which at $29.95 includes free shipping. Unless you want two cans of the sealant (which DoubleHorn calls “Clear Protective Coating”), it pays to just get the kit and have some bits left over for other projects.
Allpar trial #3: the 3M sandpaper disc and sealant kit
The headlights relapsed after just a year, and by October 2010, we had to do it again. This time, we simply bought the $15 3M kit at the local AutoZone. It attaches to a drill, and while mine is a fairly cheap model, I was able to keep it at roughly the right speed by keeping it fairly slow, while much faster than a cordless screwdriver. Again, I started out with a coarse grade of sandpaper, only it was on a Velcro-ized disk; this step took only a few minutes, as did the next two, which both involved finer grades of sandpaper. Finally, I squeezed some of their included polish onto their foamy thing, and the result was — better than the hour or two I'd spent the first time, manually wet-sanding.
3M’s instructions, with photos, are fairly clear, and their kit is easy to use; what’s more, I can use the same kit next year.
Those of you who can remove your headlights or feel comfortable spraying it, I was told by someone who should be trustworthy that clear engine spray paint may hold off the aging. If the headlights revert again next year, and there’s no reason to think they won’t, I’ll probably give it a shot.
In the end, our conclusion is that if your headlights are just foggy, and do not look as though they’ve been coated with a baked-on gunk (as ours did), you should try the least abrasive means possible. If your headlights need more work, a drill-based kit, like the 3M one we used, is the way to go, in conjunction with sealant.
Allpar trial #4: Crystal View Headlight Restoration Kit Review
One solution to the headlight issue is selling the car, though some might call that overkill. Trial #4 occured one year after Trial #3, but was done by the new owner...
Available At: Advanced Auto Parts, www.myheadlight.com, and other stores; cost, $20-25
Crystal View Chemicals has a headlamp restoration kit I recently used on a 2000 Chrysler 300M. The “M” had significantly fogged lenses, and I admit to being a bit skeptical to how well any off-the-shelf kit would work.
I decided to try CV’s option because it provides a clear coat sealant as part of the kit to help protect against future clouding. The kit comes in a foil envelope with pieces of brown and blue sandpaper (colors are used to differentiate between grits, instead of the numbers), along with packets of “CV-1” (polishing compound), “CV-2” (clear-coat sealant), and cloth applicators. This is what the headlamps looked like prior to treatment, next to the CV Restoration Kit:
I was impressed with how easy this process was. Many folks often shy away from trying to restore their headlamps themselves out of fear their sanding skills are not up to snuff. While a fair amount of elbow grease is required, the materials provided with the kit do most of the work for you, and the directions are clear and concise.
If you elect to do this process with the headlamps installed on the vehicle (as I did), I would recommend taping off the hood/front fascia (bumper cover) areas with masking tape to avoid any accidental damage to the paint from the sanding and clear-coat sealant application. This simple, five-minute precautionary step can save you from accidentally damaging the paint with a runaway swipe of the sandpaper.
The process begins with wet sanding the lens with the brown sandpaper. After the lens has been evenly sanded, wipe the lens clean with a towel and move on to the finer-grit, blue sandpaper to repeat the process. Then, using one of the applicator cloths, polish the lens evenly with a small amount of the CV-1 compound until it completely dries. Once all remaining residue has been removed/wiped away, a fresh applicator cloth is used to apply the CV-2 in swipes going in one direction across the lens. Here are a few pictures of the end result on the M:
Given the fact that this was done a little over a week before this article was published, I cannot speak to the longevity of the CV kit’s treatment. The results will vary depending on how diligent you are on the sanding, as well as application of the clear-coat sealant. I noticed a definite improvement in night visibility, and the overall appearance of the car was greatly improved.