Why Do Clear Plastic Headlight Covers Become Hazy Over Time?

Clear plastic headlight covers for cars and trucks can become cloudy or hazy over long periods, often within 10 years. This issue can be attributed to several factors, including the application of protective coatings and UV exposure. Understanding these factors can help you effectively restore your headlights or avoid the problem altogether.

Protective Coatings and UV Exposure

When new, the plastic lenses on headlights have a protective clear lacquer applied to them. This coating serves to shield the underlying plastic from harmful ultraviolet (UV) light and environmental elements. Over time, this protective coating can degrade, exposing the plastic to UV light, which leads to discoloration. This degradation can result in the headlights appearing cloudy or yellow.

Causes of Haze and Cloudiness

Sunlight Exposure: The main culprit behind the haze in headlight covers is often prolonged exposure to the sun. Sunlight contains UV rays, which can cause the plastic to degrade, resulting in cloudiness. This degradation is a natural effect of photodegradation, a process where materials break down when exposed to light, particularly UV light. Due to the nature of the plastic used in headlight covers, this degradation can lead to a cloudy appearance.

Cleaning Agents: In addition to sunlight, some cleaning agents can damage the protective clear-coating on headlight lenses. If you suspect that this is the case with your headlights, it is crucial to use gentle cleaning methods to restore them.

Restoration Kits: For many users, the best approach is to use a restoration kit. These kits often contain solvents that can remove the degraded plastic and a new clear coat to restore the lens. The steps typically include:

Thoroughly clean the lamps with normal soapy water. Apply the solvent impregnated wipe to dissolve the degraded layer. Clean with soapy water again. Wipe dry and apply the new clear coat.

In cases where the degradation is more severe, using wet and dry paper and a new clear coat is necessary to prevent further deterioration.

Short-Term Fix: For a quick solution, applying a product like WD-40 can provide a temporary fix. However, it is important to follow up with a proper cleaning and restoration process to provide a more lasting solution.

Prevention and Maintenance

To prevent headlight haze, it is advisable to:

Store your vehicle in a shaded or covered area whenever possible to reduce exposure to sunlight. Clean your headlights regularly with a mild cleaning solution to remove road grime and dust. Consider investing in a headlight restoration kit to maintain clear vision. Replace older headlights with newer, more durable models if budget allows.

Regular Maintenance: To keep your headlights looking their best, it is recommended to perform restoration every 50,000 miles. This process can be completed in about an hour, making it a manageable task for any car owner.

Conclusion

The cloudy appearance in clear plastic headlight covers is largely due to the protective coating failing and UV exposure, leading to degradation. By understanding the root causes and implementing proper care, you can restore or prevent the haze in your headlights. Regular maintenance and proper cleaning techniques are key to extending the life and performance of your headlights.