Newbie with a windshield question

No idea how that could happen, but if you're sure that nothing hit it I'd take it into the dealership and show it to them, it's possible they might replace it under warranty if they determine it was defective. If not, most insurance policies have glass coverage that doesn't cause your rates to go up if you make a claim, although those mostly have either $50 or 100 deductible. Still, that's waaaaaayyy cheaper than having to replace the windshield out of your own pocket, you'll not like the price the dealer would quote you.

 

Even a little rock, if it hits just right, can start a crack. Get it fixed, it's a safety issue. Many insurance companies cover windshield replacement if the crack is big at no cost.

 

Get it replaced with a Toyota windshield, warranty or not. I'd be suspicious that an aftermarket glass that large would install perfectly.

 

It doesn't sound like you can get it repaired either. Here is a guide.

AUTOGLASS® UK: Repair or replace?

Some insurance companies will pay for repairs but replacements incur an excess.

Post a picture of it. It may be that some materials engineer could identify it as a stress fracture from badly installed glass

 

In January I got a very small stone chip in my window on the upper right corner. I had the car less than 24 hrs and it had 35 miles on it. Within 3 days, the chip grew to a horseshoe shape about 6 inches across. The temp dropped to near zero (Connecticut) and the crack spider webbed into whole right side top to bottom. I got it replaced with aftermarker OEM and it has been fine since. No problems. Good luck.