Sika (China) Ltd. took notice from the article on the case of Mr. Zheng. Sika is the world's largest producer of polyurethanes and the leading supplier of adhesives for windscreen replacement in the aftermarket globally.

The business practice described by the article is not a rare case and happens all around China. 4S Shops seem to be the quality service place for repair and maintenance do not necessarily use products that meet the standards of the car producer. In addition it is common practice that the installation of new windscreens is outsourced to glass fitters.

Safety Risks


The windscreen and the bonding are designed to prevent you from ejection during a car crash. If you ever experienced a low speed collision, you might remember that already at low speed you are lifted out of your seat. The mass inertia keeps your body moving ahead while the car is breaking stopped. In a collision at higher speed your body could move on, hitting the windscreen or case the windscreen gets loose, being ejected onto the road.

Based on statistics, the risk of severe injury or death is much smaller if you stay inside the car than if the body is on the road.

Airbag unable to protect

The airbag is one of the most important passive safety elements of your car. In case of an accident it is designed to slow down the movement of the occupants body and protect from injury. This only works if the airbag is able to transfer the force to a backboard. In many cars the windscreen is required to do that, especially on the passenger side. See by yourself how much force an airbag can apply to the windscreen just by blowing up.

Roof Crush

The windscreen is a structural member of the car body and if properly installed it will prevent roof crush which can occur in a roll-over accident. Roll-over accidents are amongst the most severe accidents as they account for a large portion of severely injured or death occupants (Data from US Statistics). Roll-over accidents occur more often to Sports Utility vehicles (SUV) than normal cars, this is due to the higher center of gravity in these vehicles. The roll-over test video on top shows such an accident.

Evidence in the Chinese Market

In China there is no nationwide accident statistics available. But seeing sites as evidence of dramatic accidents can be found. We were able to easily find some accident pictures that clearly show that the windscreen installation was not sufficient to protect the occupants. Of course it is not possible to track the root cause of each accident from this page but it shows alarming signs about the quality of aftermarket windscreen installations in China.

Subcontracting Business Practice

Today almost all passenger cars are equipped with bonded windscreens. For the bonding process high performance polyurethane adhesives as well as cleaners and primers containing adhesion promoters are used. In the automobile factory the quality of the adhesive and the glass is under control and the car manufacturers are using standardized, automated processes for the application of the products as well as the installation of the windscreen. As the windscreen is part of the structural design of the car and required to meet all the safety standards, the requirements for the original adhesive are very high.


Even though the adhesive is probably the smallest cost of the total cost of the job but has a large impact on the final result, many service providers tend to save repair cost by using inferior adhesives in the Chinese Aftermarket. It’s not easy to get an adhesive that meets the original requirements for your installation. Going to a 4S shop does not necessarily mean you get such a product as many 4S shops use subcontracting for that kind of work. You might get the original glass, as there is a logo on, but you might not get the original adhesive.


Many technicians are unaware of the importance of cleaning windscreens or protection of your vehicle during the job. Aftermarket windscreens might be produced using a different technology of production resulting in different quality or might got contaminated during transport or storage. The job in the aftermarket is more difficult than in the factory and the process is not standardized, but depends on the capabilities of the technician doing the job right.

Non-Sika products

Sika is known as the world's leading manufacturer of windscreen adhesives for automotive aftermarket as well as a supplier to production lines of many car producers including Porsche.

Lately Sika has noted a kind of product used by some Porsche 4S Shops and their Subcontractors. The product uses similar packaging and decoration of Sika windscreen adhesives, which is quite likely to cause confusion with Sika’s genuine products. Since these products may not meet technical requirements and standards, they are liable to endanger your safety. We kindly draw your special attention to the trade dress of Sika’genuine products and the brand and logo of Sika.

Safety Tips

Use a reputable company to have your windscreen replaced. Supervise the installation and ask the 4S or glass shop to provide you with the empty packaging of all parts that have been used for the installation. Good companies will tell you about the required Safe Drive Away Time of the adhesive and typically an installation requires one hour to complete followed by the Safe Drive Away Time which indicates the time the adhesive requires to build up enough strength so that the car can be operated safely.