How to Identify the Production Date of Car Windows?
3 Answers
Methods to identify the production date of car windows: 1. The production date of car glass can be determined by a code located at the bottom left or right corner of the window glass. Look for a number and several small black dots in the last or second-to-last row; 2. The number represents the production year of the glass, indicating the last digit of the year. The production date of the glass and the vehicle will not differ by more than 10 years; 3. The small black dots indicate the production month of the glass. If the dots are in front of the number, subtract the number of dots from 7. If the dots are behind the number, subtract the number of dots from 13; 4. Some glass may also have a few larger black dots following the production year and month, which indicate the specific week of the month. For example, 5 dots represent the first week; 4 dots represent the second week; 3 dots represent the third week.
When I first bought my car, I also researched the date on the window glass. It's actually about reading that small string of codes in the corner of the glass. The usual format is a number followed by dots, with the dots either before or after the number. For example: if the number is 20 and the dots are in front like ···20, it means April 2020 (subtracting the number of dots, 3, from 7). If the dots are after the number like 20··, then it's November 2020 (subtracting the number of dots, 2, from 13). I remember the mechanic reminded me when changing the spare tire to clean the glass properly to see clearly, especially after rain when water stains can cover the marks. Different car manufacturers place the codes in different locations—some on the lower left corner of the windshield, others hidden on the edge of the side window. Checking the date not only tells you how old the glass is, but if you're buying a used car and find the glass date is later than the vehicle's production date, it's likely been in an accident and had the glass replaced.
I work in the auto parts industry and deal with various car windows every day. Simply put, it's about focusing on the small markings at the corners of the glass, usually consisting of letters, numbers, and dots. The key is to look at the year digits and the distribution of black dots: for example, if you see the number 22 and two dots on the right, the calculation method is 13 minus the number of dots (2), which equals 11, meaning it was manufactured in November 2022. The most common issue occurs during winter when the glass corners are completely covered by ice and unreadable, requiring de-icer treatment. What some car owners often overlook is that the rear window also has a date code near the heating wires, but the font is extremely small and requires a magnifying glass. When a window needs replacement due to a crack from a stone impact, we always verify this date code first to ensure the part matches.
