Glass versus plastic headlight lenses

[eggsalad]

35 years ago, you didn't see old cars with yellowed or fogged-over headlights, because every time you bought a new headlight bulb it came with a free, brand-new, reflector and lens. Were sealed beams objectively worse than modern composite headlights? Mostly. But a 10-year-old car with sealed beams probably has better headlights than a 10-year-old car does today.

 

[alpg88]

35 years ago, you didn't see old cars with yellowed or fogged-over headlights, because every time you bought a new headlight bulb it came with a free, brand-new, reflector and lens. Were sealed beams objectively worse than modern composite headlights? Mostly. But a 10-year-old car with sealed beams probably has better headlights than a 10-year-old car does today.

the reason you did not see, is because 35 years ago most cars had glass headlights, not polycarbonate. my first cars were 1986 chevy cavalier, 1985 cutlass cierra, and 1987 delta 88, all had glass headlights. My friend's volvo 240 from mid 80s also had glass headlamps. i have not seen a glass headlight on cars made starting in early 90s. now even 100k bmw and mb have polycarbonate headlights. do not know about newer RR or Bentley, we do not get many of those in our shop.

 

[Alaric Darconville]

Even if the lens itself is glass, the reflector can degrade. Still, I'd like to see us at least eliminate lens degradation.

Glass-lensed composite headlamps starting in '90 are a bit rare, but I know the '95 (and presumably other years) Estima in the ECE had them.

 

[eggsalad]

Even if the lens itself is glass, the reflector can degrade. Still, I'd like to see us at least eliminate lens degradation.

Glass-lensed composite headlamps starting in '90 are a bit rare, but I know the '95 (and presumably other years) Estima in the ECE had them.

I had a '90 Acura Integra that had glass composite headlights.

 

[Qship1996]

My 1996 Infiniti Q45 had great big glass headlights, originals went to the boneyard 20 years and 315,000 miles later with the rest of the car due to structural rust on frame rails with original engine and trans operating as new

 

[alpg88]

Whether they were better or worse depends who you ask. someone that drives old cars, may like that lenses are always clear, no yellow haze to deal with. for someone who gets new cars, drives 3 years then replaces, it makes no difference, 3 years is not enough for lenses do get yellow, none of my new cars had any noticeable yellowing, even thou my cars are parked outdoors.
But in any case, glass lenses are no longer available, there may be exceptions however. maybe in different markets they still use glass, but in usa, they are basically extinct now.

 

[aznsx]

Can't vouch for accuracy of this, but [Link to sketchy commercial website removed by moderator]

Are glass headlights illegal?
No, they are not illegal. Although glass headlights are scarce owing to their cost and high manufacturing cost, glass headlights are not outlawed, especially in Europe and most parts of the world.

In the United States, however, the Department of Transport (DOTT) mandates that all headlights be made using plastic. You may find some cars with plastic headlights in the United States shipping with glass headlights in Europe and other parts of the world.

 

[-Virgil-]

In the United States, however, the Department of Transport (DOTT) mandates that all headlights be made using plastic.

This is not true, and never has been.

 

[aznsx]

This is not true, and never has been.

And to be absolutely clear, I did not say that, but was quoting a source the link to which you removed.

 

[bykfixer]

I've never had a flying rock hit a plastic lens and cause it to crack like a glass one did once. Other than that it really doesn't matter to me. But I do like being able to simply "windex" the headlight lens of a classic car instead of polishing the oxidized film off the 20 some year old plastic lenses on my older vehicle.

To me, keeping plastic lenses clear isn't anything more than maintenance like rotating tires or waxing the finish from time to time.

The thing that seems to cause me the most grief is a dirty windshield. That issue is what seems to cause glare from oncoming vehicles or reduce my vision.

 

[Alaric Darconville]

Can't vouch for accuracy of this, but [Link to sketchy commercial website removed by moderator]

Are glass headlights illegal?

In the United States, however, the Department of Transport (DOTT) mandates that all headlights be made using plastic. You may find some cars with plastic headlights in the United States shipping with glass headlights in Europe and other parts of the world.

I can vouch for the inaccuracy of this.
"DOTT" is just icing on the cake for how wrong this is.

 

[Alaric Darconville]

for someone who gets new cars, drives 3 years then replaces, it makes no difference,

And when you trade in that car, someone else may end up with it, and they have to deal with it. And maybe you, if you end up sharing a segment of road with your former car.

 

[alpg88]

The thing that seems to cause me the most grief is a dirty windshield. That issue is what seems to cause glare from oncoming vehicles or reduce my vision.

You mean haze on the inside??? yep, agreed, This is plastic of the dash gassing off. The residue is hard to get off, and when you do it comes right back. but there ways to get rid of it, we experimented with a lot of things in the shop, but it is a topic for a different section.

 

[scootertrs]

I personally crave for glass headlights. I just passed by a Chevrolet new car lot with several new Corvettes and most if not all already had fogging on the headlights. A brand new car. What gives? My 2021 Sorento has droplets forming in the fog lights. Kia says that unless it pools at the bottom, its OK and not warranty issue. I know my '65 Vette with Glass headlights is as bright and clear as the first day.

 

[Hilldweller]

When I become King, I'm going to mandate standardization of headlights. 7" round, easy to replace, upgrade as technology moves forward. Fits a Miata, fits a Jeep.
I had a pair of JW Speaker Evos in my Jeep for over 150,000 miles, used well, and they still looked fine on the day the Jeep blew up.

JW Speaker continues to improve the breed to this day.

 

[scootertrs]

. 7" round,

The ideal size and shape for maximum light transmission!

 

[Alaric Darconville]

The ideal size and shape for maximum light transmission!

Any theoretical advantage of one or the other is never realized in the finished product because the advantage only exists when "all things being equal", which they never are.
A good headlamp of [shape X] will always be better than a bad headlamp of [shape Y]. A good headlamp of [shape Y] will always be better than a bad headlamp of [shape X].

 

[-Virgil-]

I personally crave for glass headlights. I just passed by a Chevrolet new car lot with several new Corvettes and most if not all already had fogging on the headlights.

...not. Sorry, this didn't happen. You saw dirt or a protective film not yet removed from the lamps, but no, you didn't see brand new cars with clouded-up headlamps.

My 2021 Sorento has droplets forming in the fog lights.

Totally separate issue, and it can happen to any unsealed lamp, no matter whether the lens is made of plastic, glass, or transparent duranium alloy.

 

[scootertrs]

My Cibies never did, even after 20 years? My Hellas never did? And I went up close to the Corvettes and they had no protective covering, I am sorry to say, being a lifelong Chevy fan!

 

[-Virgil-]

And to be absolutely clear, I did not say that, but was quoting a source the link to which you removed.

Yes, clear on that. I sent Daniel Stern that bogus (now deleted) link, and he sent me this link back, with a step-by-step proof of why glass lenses are better in the terms that matter (crashes/deaths).