How to Check the Production Date on Glass?
4 Answers
Here are the methods to check the production date of automotive glass: 1. The production date of the glass is usually located in the code at the lower left or lower right corner of the window glass. 2. The date is represented by small dots and numbers, where the number indicates the production year, and the dots indicate the month. The specific representation methods are as follows: (1) The number is the production year of the glass, representing the last digit of the year. You can determine it based on the vehicle's manufacturing date. (2) The small black dots indicate the production month of the glass. Some glass has the dots in front of the number, while others have them behind the number. (3) If the black dots are in front of the number, subtract the number of dots from 7. If the black dots are behind the number, subtract the number of dots from 13. The result is the production month of the glass. (4) Some glass may also have a few larger black dots after the production year and month, which are used to specify the week of the month.
I always teach my friends this trick when helping them check cars. The code in the corner of the glass is quite interesting. For example, an '8' followed by five dots and then three more dots, right? The '8' stands for 2018, the five dots on the left mean 7-5=2 (February), and the three dots on the right indicate the second half of the year, 13-3=10 (October), so it was manufactured in February 2018. Different brands may place the symbols differently—Hyundai likes to print them under the side window edge, while BMW tends to hide them in the lower right corner of the windshield. Once, while inspecting a used car, I found a two-year gap between the dates on the windshield and the side windows, clearly indicating it had been in an accident and had its glass replaced.
Just taught my neighbor how to read this last week. Look for symbols with numbers and dots on the glass corners. For example, if you see a '6' with seven dots, and the dots on the right side of the number are divided into two rows, that means it was manufactured in 2016. The key is to observe the position of the dots: if all the dots are on the left side of the number, the month equals 7 minus the number of dots; if the dots are on the right side, it's 13 minus the number of dots. The dots on my old Toyota were printed next to the rear window heating wires, and I had to clean them with alcohol to see clearly. Remember to wear polarized glasses to make finding the symbols easier, as reflections in the sunlight can cause you to miss them.
Once, a mechanic taught me this super simple trick: the number represents the last digit of the year, and the dots are the month code. Don't panic if you see dots on both sides of the number—the dots on the right alone indicate the month in the second half of the year. For example, a combination like 2••• and ••• means it was produced in March 2012—subtract 3 from 7 for the left dots to get April? No, no, if there are no dots on the left, it's the first half of the year, and with three dots on the right, subtract 3 from 13 to get October! Imported car symbols are often hidden under the door glass seal.
