How to Check the Date on New Car Glass?

[SanLeo]

Method to check the date on new car glass: There is a code at the bottom left or right corner of the window glass. In the last or second-to-last row, there is a number and several small black dots. The number represents the production year of the glass, and the production date of the glass and the vehicle will not differ by more than 10 years. If the black dots are in front of the number, subtract the number of dots from 7; if the black dots are after the number, subtract the number of dots from 13. The result is the production month of the glass. Generally, the glass used by OEM suppliers is zero-inventory, meaning the glass is fully matched by the glass manufacturer before the vehicle rolls off the assembly line, so the production time of all the glass in the vehicle is basically the same. If they differ, it can be concluded that the glass was removed and reinstalled during the assembly process, indicating a reworked vehicle. Of course, this rework does not necessarily indicate a quality issue—it might just be a minor problem during production.

[DelSavannah]

Reading the date on car glass actually has its tricks, which I learned from a veteran at the dealership. Look for the combination of small black dots and numbers in the corner of the window. The number represents the last digit of the year, and the dots represent the month. Dots before the number indicate the first half of the year, while dots after the number indicate the second half. Here are two examples: If you see '..8' with two dots before the number 8, it means May 2018 (7 minus 2 dots equals 5). If you see '8..' with two dots after the number, it means November 2018 (13 minus 2 equals 11). Note that the date on the windshield might differ from the side windows, so each piece of glass must be checked individually. Always compare it with the vehicle's manufacturing date on the factory plate. If the glass date is later than the manufacturing date, it's definitely been tampered with, and you should clarify this with the dealership. Some luxury cars use more complex letter codes, in which case referring to the brand manual is the most accurate approach.

[DiMiguel]

I remember when I picked up my new car, I spent a long time studying the date markings by the window. There's a dotted numeric code in the lower left or right corner of the glass. The number 8 represents 2018, and the number of small dots before it determines the month: two dots mean May (7 minus 2 equals 5), three dots mean April (7 minus 3 equals 4). When the dots are after the number, the calculation is different, for example, one dot after 8 means December (13 minus 1 equals 12). In practice, you should bring a cloth because grease can obscure the markings. After checking the date, you also need to verify it against the purchase invoice date—normally, the glass date should be earlier than the invoice date. If you encounter unusual dot positions, don't panic; some imported cars use diamond symbols instead of dots, but the principle is similar.

[McLouis]

The glass date is marked at the corner of the window, consisting of numbers and dots as the core information. The number indicates the year, for example, the number 8 could correspond to 2018 or 2008, which needs to be determined in conjunction with the vehicle's manufacturing time. Dots before the number indicate the first half of the year, with the month calculated by subtracting the number of dots from 7; dots after the number indicate the second half of the year, with the month calculated by subtracting the number of dots from 13. For example, for the number 2023's 3, three dots on the right mean 13 minus 3 equals October. Special symbols such as asterisks or triangles require consulting the specific vehicle series manual. Dates on different glass positions may vary, but any date later than the vehicle's manufacturing date must indicate a replacement part. Professional inspection also requires the use of a UV light to identify laser engravings.

[EloiseAnn]

During a visit to a glass factory, I finally understood the meaning of these markings. When molten glass is formed on the assembly line, the machine automatically sprays date codes, just like birthday labels. The numbers represent abbreviated years, while black dots indicate the month by their position and quantity—dots on the left for the first half of the year and on the right for the second half. For example, five small black dots to the left of the number represent February (7 minus 5 equals 2). This system is globally standardized, though Lexus prefers using the letter 'B' instead of dots. Interestingly, the rear windshield defroster wires can obscure the markings, so they must be observed from the outside. It’s normal for glass dates to be 1-2 months earlier than the vehicle's production date, as assembly time needs to be accounted for. This concentration of glass dates is even more noticeable in facelifted models.