How to Check the Production Date of Glass
3 Answers
The production date of automotive glass is usually marked at the lower right corner of the window or below the logo. It is presented in the form of a single digit. The markings on the glass can provide information about the brand, structure, specifications, and production date of the glass. There are two main types of production date markings for automotive glass: The first type: Number + small black dots: The number represents the last digit of the production year. If the small black dots are in front of the number, subtract the number of dots from 7 to get the production month. If the small black dots are behind the number, subtract the number of dots from 13 to get the production month. The second type: Number + small and large black dots: This representation is relatively simpler. The leading number represents the last digit of the production year, the small black dots represent the quarter, and the large black dots represent the month within that quarter. However, some cars are special, such as BMW, whose glass does not use the above two methods (some imported models also follow this pattern). If you want to know the production date of such automotive glass, you need to enter the serial code on the glass and query it through a website, which is relatively more complicated.
Last time I washed my car, I noticed some small dots near the windshield. At first, I thought they were meaningless, but after checking, I realized they were production date markings. Usually located in the corners or edges, these markings consist of dots and numbers. For example, small black dots: larger dots surrounded by smaller dots indicate the year, while dots inside a square box nearby represent the month. Taking my car as an example, I saw one dot surrounded by 7 smaller dots, which stands for 2017; and 8 dots inside a square box on the right, meaning it was produced in August. Counting this way, my windshield has been in use for several years, so I need to pay attention to aging issues. If there are cracks, I should replace it early. Checking this occasionally helps determine whether the glass is original or if it has expired, preventing potential dangers in winter when it becomes brittle. It feels like a handy little trick, quite interesting. I also share this with my friends—simple and practical.
Checking the production date of car glass is actually quite straightforward. Generally, you can find the printed code near the corner of the glass or the frame. The method I commonly use is the dot counting method: there are two types of dots. One is with small circles next to them, combining dots and numbers. Dots outside represent the year, for example, ·7· stands for 2017; dots inside the frame indicate the month, with 8 dots representing August. Sometimes, a numerical format is used, such as 2304, where the first two digits '23' represent 2023, and the last two digits '04' represent the 4th week. When checking, wipe the corner clean with a cloth and look carefully—it's not hard to find. The key point is that this helps you identify the lifespan of the glass. Aged glass has poor pressure resistance and is prone to shattering at high speeds or during accidents. I recommend checking periodically; it applies to both new and old cars to prevent safety hazards in advance.
