For 1990-2009 cars

1. Remove any trim that might obstruct your view.
2. Have a helper inside the vehicle to detect the actual leak point.
3. Use a unrestricted water flow (a hose with no nozzle).
4. When water testing weatherstrips:

• | Aim the water so that the water falls only on the window side or only on the body panel side of a weatherstrip, or tape across the weatherstrip between the body panel and the weatherstrip.

• | Remove the tape and test again. This will help in determining whether the leak is between the weatherstrip and the window or between the weatherstrip and the retainer.

5. Begin the water test at the base of suspected leak area and move slowly upward.
6. Mark the location of the leak.