For 1990-2009 cars

1. Dust will leak into the vehicle where water will not.

This particularly happens in the lower portion of the interior.

2. Forward motion of the vehicle can create a slight vacuum which pulls air and dust inside the vehicle.
3. In order to determine the location of dust leaks, perform the following steps:

3.1. | Remove the mats from the floor.

3.2. | Remove the mats from the toe panel.

3.3. | Remove the insulation from the floor.

3.4. | Remove the insulation from the toe panel.

3.5. | Drive the vehicle on a dusty road.

3.6. | Examine the interior.

Dust in the shape of a small cone or slit will usually be found at the point of leakage.

3.7. | Mark the points of leakage.

3.8. | Shine bright lamps on the underside of the floor and the cowl.

Darken the interior when performing this step.

3.9. | Have an assistant inspect the inside of the vehicle for any points where the light shines through.

3.10. | Mark the leakage points.

3.11. | Inspect the weld joints.

3.12. | Inspect the body mounts.

3.13. | Seal the leaks with an air-drying, body-sealing compound.