Leak test: how it is checked that no water gets into the interior of cars

Have you ever wondered how car manufacturers manage to prevent water from getting into the cabins of their models? Well, today we answer this question with Stellantis. These are the leak tests the group carries out at its plants in Vigo, Zaragoza and Madrid. Watertightness is one of the most special manufacturing processes, and it has to finish with very high quality.

Consider this: all the work on the assembly line can come to nothing if the model does not pass the leak test. According to Stellantis itself, “the vehicles in the ranges produced in Spain undergo a series of tests to verify whether water enters the cabin, detecting even the slightest leak in order to offer a 100% watertight product.”

This is Stellantis’ leak test

During the manufacturing process, and to prevent water from entering the interior of the car, different types of sealants are applied, creating beads that block the passage of water. In addition, at the Vigo plant, parts called inserts gonflants are used, which act as sealers and provide watertightness when the model passes through the paint drying area. Likewise, a adhesive called gurit is used on the windows, and rubber seals on the doors.

Stellantis assures that throughout the process materials are used that resist even oxidation, such as polycarbonates, polypropylenes, polyamides, polyethylenes, acrylonitrile butadiene styrene and even alloys. Once the cars are sealed, they reach the key point: the leak test. If the car fails the test and water gets in, it has to go back to the assembly line. Stellantis wants airtight cars, to keep out water, dust, smoke and even dirt!

In Vigo, the Peugeot 2008, the Citroën Berlingo, the Peugeot Partner and the Opel Combo go, as standard, through a shower lasting four to five minutes. During this time, not a single drop of water should enter the cabin. In Madrid, the Citroën C4 is examined, and in Zaragoza the Opel Crossland X, the Opel Corsa and the Citroën C3 Aircross.

Not content with that process, the units are subjected to a tropical shower of about 30 or 40 minutes, in which the flow exceeds 30 ml of water per minute. The car is tilted up 20 degrees and passed through all angles and directions. To give you an idea, each Stellantis model receives about 900 litres of water per square metre at a pressure of 150 bar. Afterwards, the cars pass through a drying tunnel so that a technician can then inspect the cars one by one.