Mercedes-Benz owners will have to keep their sunroofs shut after the brand announced a recall for flailing units that could fly off at a moment's notice. The German manufacturer first became aware of this issue on older models in 2017 and has now issued a recall for Mercedes C-Class, CLK, E-Class, and CLS models sold between 2001 and 2011. The issue seems to be a weak bond between the glass sunroof panel and the sunroof frame, and in some cases, the sunroof can completely detach, causing significant safety risks for both the occupants of the car and other road users. This news comes after Mercedes-Benz had to issue a number of recalls for other minor issues that slipped past the pre-delivery inspection.

According to documents filed with the National Highway Traffic Safety Administration (NHTSA), Mercedes-Benz first became aware of this serious issue in 2017 when reports started flooding regarding defective sunroofs in international markets. When first investigated, Mercedes-Benz couldn't pinpoint the problem and even got a third party to investigate the issue, but the results were once again inconclusive. In 2018, Mercedes-Benz analyzed more sunroofs and discovered that those showing issues were manufactured later on in the production cycle and reasoned that the issues stemmed from a shortened drying time for the bonding agent that attaches the sunroof to the sliding framework. The company realized that sunroofs that underwent a drying period of two minutes instead of five minutes showed signs of degradation.

By 2020, Mercedes-Benz found that cars that had been drying for five minutes also started showing signs of failure. Mercedes was finally getting closer to the root of the problem. By 2022 Mercedes eventually traced the issue to the bonding agent, which would degrade over time. Factors in the production process, such as temperatures and humidity in the production facility, led to the issue. Now that the issue has finally been pinpointed, Mercedes-Benz is recalling a vast number of cars manufactured between 2000 and 2010. Mercedes-Benz will contact affected owners by 21 February and ask them to visit their nearest dealer for an inspection and replacement if necessary, but you can also check your own VIN on the NHTSA's website. With cars getting more complex by the day - the latest C 63 is a prime example - we hope that quality issues like this don't crop up again.