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How to Prevent Headlights from Yellowing

How to Prevent Headlights from Yellowing

It’s crucial you learn how to prevent headlights from yellowing since they do all the time under certain circumstances. This is the best way to maintain the lenses and ensure a safe drive at night.

Foggy headlights are ugly and can reduce visibility by over 50% while driving. They also prevent other road users from seeing you and can lead to a fine or, worse, a driving suspension.

Don’t fret; you will learn tweaks you can leverage to prevent headlights from yellowing in this write-up. But first, let’s explore the causes.

Causes of yellowing on headlights

Image: Headlight

Most headlight lenses are pure solid Polycarbonate or a blend of acrylonitrile butadiene styrene plastic.

They are also vulnerable to fogging and dullness despite the materials withstanding harsh conditions. If your headlights turn yellowish, the following could be the cause.

1. Oxidation

Headlight oxidation is a top cause of decreased visibility for most cars. It results from exposure of polycarbonate lenses to the air and UV radiation.

When direct sunlight hits the lenses, it causes microscopic cracks. The cracks can let in moisture that leads to yellowing.

Related: Neutralizing rust on cars

2. Water vapor

Car manufacturers fit headlights with watertight seals, which wear and often break. As a result, water can get in and condense, forming a fog that is hard to wipe out.

This scatters the light’s beam and impairs your nighttime visibility while driving.

Image: Headlight

3. Flying debris

Your car takes a beating from road gravel and other debris as you cruise down the road. These substances stick in the headlights, wearing them down and causing scratches and a cloudy appearance.

4. Chemicals

Headlight lenses absorb a thin layer of chemical substances after being in use for some time.

This dims the light’s beam, reducing visibility. The chemicals can be from the surrounding environment or engine emissions.

Read: How to check if water has entered engine

Image: Headlight

How to Prevent Headlights from Yellowing

You can restore, prevent, and remove haze from headlights. The best part is you can do it on your own by using the following techniques:

1. Wash the car

Most car experts recommend washing a car, but some drivers overlook the headlights. It is worthwhile cleaning the lenses with automotive soap to remove debris that could cause cracks.

The only downside to this technique is you will need to wash the lenses several times to see the results.

2. Park the car under a shade

Parking your car under a shade or in a garage is an effective way to prevent headlights from yellowing.

If you lack these options, you can face the headlights away from direct sun rays. Achieving this will reduce UV radiation exposure and wear on your car.

Image: Headlight

3. Polish the headlights

Polishing yellow headlights is the best way to restore optimal night visibility.

It is advisable to use a microfiber cloth and a non-abrasive polish to wipe the lenses as soon as you see signs of yellowing. You can also use a buffing machine, but be careful not to burn the lenses.

Also Read: Signs of a bad car battery vs alternator

4. Soak in Vinegar 

Restoring headlights with vinegar requires removing the lenses and soaking them for about one hour. Next, use a rough cloth to rub the grime before rinsing and reinstalling the lenses.

Be gentle while scrubbing the dirt. You can also apply a polishing compound to gain a clear finish on the headlights.

Image: Headlight

5. Polish with baking soda or toothpaste

Baking soda and toothpaste are cheap headlights restoration remedies you can use at home. You can apply toothpaste with your fingers on the lenses.

As for the baking soda, mix it with water to form a paste first. Use a brush to scrub the lenses in small circular motions. Wipe the paste with a microfiber cloth and rinse to reveal the results.

6. Sand the headlights

Sanding the headlights works well to remove oxidation on the lenses’ outer layer.

It will work well if you use several pieces of different grit sandpaper—400, 800, 1,000, and 2,500. Start sanding with the 400 grit sandpaper and finish with 2,500 grits.

You also need a soft sponge or cloth to wipe the dirt and apply polish. The best part about sanding is it removes even the tiny gouges on the lenses.

This provides a flat clear surface to apply polish and restore the sparkling shine on the headlights.

Image: Headlights

7. Seal the headlights

Allowing water and moisture to penetrate the headlight makes the plastic brittle. But again, you can apply clear coat sealant to prevent water from penetrating and condensing inside the lenses.

Leave the sealer to dry for about 20 minutes, depending on the weather. You can also enhance the clarity of the lenses by applying restoration cream.

Image: Bright Headlights

Frequently Asked Questions on Prevention of Yellowing of Headlights

Is it okay to wax plastic headlights?

As a general recommendation, waxing is an additional preventive measure you can use to avoid future deterioration on the headlights.

How can I maintain the headlights?

A clever way to ensure the headlights stay in perfect shape is to clean and wax them regularly. Achieving this keeps debris and sediments from sticking or damaging the lenses’ surface.

Which restoration kits are the best to illuminate the headlights?

You can use the Sylvania headlight restoration kit or the Turtle wax headlight lens restorer.

Does ceramic coating prevent headlight yellowing?

On average, ceramic coating effectively prevents cracks and yellowing on headlights for up to five years.

Should I apply a clear coat on headlights after sanding or polishing?

It is wise to apply a clear coat to prevent future UV damage and give the headlight beams unsurpassed clarity.

Now that you know how to prevent headlights from yellowing, the best approach to fix them is to ensure you have the right tools.

When scrubbing or washing, be sure to put waterproof tape around the lenses to prevent soapy water and dust from penetrating the inner side. If you can’t do it yourself, get a professional’s help.

Achieving this will ensure the lenses stay intact and sparkling after scrubbing or applying the sealant or polish. Also, a professional will be more likely to note microscopic cracks than you can.

Read: What causes crankshaft sensor to go bad

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