2008 Subaru Outback Headlight Lens Restoration

What needs to be done

Once upon a time, all headlight lenses were made of glass. Over time, plastic took over- they are cheaper, lighter, easier to mass produce, and are more resistant to breaking. But there is a problem. Faded and oxidized headlight lenses are seen on every old, high mileage cars that spend majority of their lives out in the open sun. The polycarbonate's UV protection wears off with time and the sun's rays fades the plastic. The best way to restore the transparency is by wet sanding the oxidation away and revealing a new layer of the plastic lens. 

A quick method used by many people is to use bug spray and clear the head lamps. DEET -the active ingredient in the sprays- acts as a solvent and dissolves the top layer of the plastic and clears up the oxidation. While this process does work immediately, I believe it does more harm. This is because it corrodes and deforms the top layer of the plastic. Also, the cloudiness comes back very quickly- as quick as a few days.

Some people also use toothpaste to clean the lens. It works to a certain extent, but the down side is that its not enough nor is it the right type of compound to use on oxidized plastics.

We will be wet sanding the headlights on my Outback and see if we can improve the appearance and light transmission. 

Products needed

• Masking tape
• 800 grit sanding paper/block (heavy)
• 1200 grit sanding paper/block (medium)
• 3000 grit sanding paper/block (light)
• Paint polishing compound (I used Menzerna 1500. 2500 can be used too)
• Water or quick detailer for lubrication and as a wetting agent.
• Few general purpose microfiber towels
• Wax/sealant/coating

Lets Get started!

First, we will wash the headlamps to clear off any bugs and dirt that we don't want to act as an abrasive. A wipe down with a quick detailer should do the job. Next, we tape off the headlamps to protect the paint from the sandpaper. A general masking tape should be good enough.

step 1

We will use the polishing compound to take a stab at cleaning the oxidation and doing some minor leveling on the lens, so that our sand paper won't have to work extra hard. Put some of the compound on the microfiber towel and start rubbing it in a circular motion. Make sure to cover the entire lens and make multiple passes to ensure uniform coverage. After you are done polishing with the compound, wipe it off, and then we can move on to sanding the lens.

step 2- Wet sanding!

We will start off with the 800 grit sand paper. Spray the quick detailer on the lens and on the sand paper and start sanding the lens firmly, going side to side (horizontally). Keep spraying the quick detailer as needed to keep the lens wet. You are done once the lens has been sanded uniformly.

The second sanding step is crucial as it will dictate the level of clarity you will ultimately get. Use the 1200 grit paper and spray the quick detailer on the paper. Then start rubbing it firmly in a up and down (vertical) motion (opposite to what you did with 800 grit paper). This cross hatching allows us to shave down the sanding peaks from a different angle. Ensure you uniformly cover the entire lens. After that, we will move to step three.

The last sanding step is to use the 3000 grit sand paper to finish the sanding and to start bringing out the clarity. Ensure there is enough lubrication and then start sanding the lens horizontally (opposite to 1200 grit) until you start seeing the lens becoming slightly clear. This is usually quickest of the three sanding process. 

Almost done

Now, we have to move to compounding. The best way to go about this is by using a random orbital buffer. But since I am away from my haveli, the elbow grease has to do. Be liberal and use enough compound on a microfiber towel and start buffing the lens. Be firm and use enough product to polish the lens. The lens should look as clear as it can be by now. Once you are done polishing, wash the lens, and apply a coating/wax to protect it from further oxidation. This is very important as we have sanded away a layer of the plastic, so the new plastic is going to be at greater risk of damage from UV rays. Applying a UV resistant coating such as a wax or sealant will help prevent it from yellowing.

last notes

Each lens took me about 10 minutes to sand and polish. For less than $5, this is a marked improvement in the visual appearance of the Outback. I have noticed that the throw my of lights (high and low beam) have almost doubled at night! I genuinely didn't expect this level of improvement in clarity of lights at night. Remember to take your time and sand in cross hatch pattern to obtain the best results. I also used the compound to polish the fog lights. 

You do need to set your expectations right. This (or any other) method won't get your headlight lenses back to its brand new original glory. But they will get very close to it. You will still have tons of rock chips, deep scratches, dents, and other imperfections that occur over time which will take away the gloss a little bit. But I definitely encourage you to use this method to increase your car's appeal and safety.