Why Do Aftermarket Headlights Turn Yellow?

[Jerry]

If the headlights replaced are not from the 4S store but are aftermarket ones, the lamp covers are made of recycled plastic. Initially, they may look almost the same as the original ones, but the specific reasons for yellowing are as follows: 1. Time Factor: Over time, the plastic lamp covers will turn yellow. 2. 4S Store: Although the original headlights replaced at the 4S store are more expensive, they use the exact same parts as those installed at the factory, ensuring quality and preventing yellowing. Additional Information: Not all replaced headlights will turn yellow, but those that do are definitely not original and are of inferior quality. Using a lower-wattage bulb can slow down the yellowing process, but plastic headlights on domestic cars will eventually turn yellow.

[RicardoLynn]

I've seen many aftermarket headlights turn yellow, mainly due to poor material quality. To save costs, aftermarket manufacturers use cheap plastics or coatings that lack UV protectants like OEM parts, causing them to degrade under sunlight. Especially when parked outdoors in summer, strong UV rays trigger oxidation inside the plastic, gradually turning it yellow. Another issue is rough surface treatment—coatings are as thin as paper, making them prone to dust and grime buildup. Aggressive cleaning can accelerate deterioration. I recall one repair case where an aftermarket headlight yellowed after just one year of use, costing the owner more to replace than durable OEM parts. Humid climates worsen the problem, as airborne pollutants stick to the lens. Without regular maintenance, issues arise faster. Ultimately, material quality and environmental factors are the main culprits.

[Kirk]

As a car owner, I once replaced my headlights with aftermarket ones, but they turned yellow quite quickly, possibly due to my parking habits. I often park by the roadside where the headlights are exposed to direct sunlight for half a day. The aftermarket lamp covers lack UV protection, and the plastic absorbs heat and deteriorates. Additionally, the city air is dirty, with dust and acid rain settling on them, and cleaning isn't thorough enough, so they gradually turn yellow. During a maintenance check, a mechanic told me that OEM headlights have a special coating for wear resistance, but aftermarket ones skip this process to cut costs. Now, I make sure to clean the lamp covers frequently with a soft cloth, avoiding hard brushes that could scratch the surface, or using protective sprays to delay aging. While aftermarket parts might save money initially, they often require more frequent replacements, which can be wasteful in the long run. Improper cleaning is also a common issue.

[SebastianLee]

I opted for aftermarket headlights to save money, but they quickly turned yellow. The reason lies in the cut corners during manufacturing, where low-quality plastics with insufficient UV protection were used, accelerating oxidation and color changes when exposed to natural elements. The effect is more pronounced in hot weather, as sunlight's UV rays degrade the plastic surface, and dust accumulation forms a yellowish layer. From an economic standpoint, while aftermarket parts are cheaper upfront, their shorter lifespan means reduced brightness after yellowing affects usability, ultimately costing more in replacements. Proper cleaning can help slow down this process.

[LaReid]

I've noticed that aftermarket headlights turning yellow can be very dangerous. Made from inferior materials lacking UV protection, the lens cover ages and discolors, resulting in dim lighting that affects nighttime visibility and increases accident risks. Aftermarket manufacturers cut costs by using basic plastics, allowing air pollutants to accumulate on the surface, where oxidation reactions cause yellowing. Compared to OEM premium coatings, improper maintenance like harsh detergent scrubbing damages aftermarket units faster. Choosing high-quality parts is recommended for safety protection.