why does my BMW 3 Series E90/E91 (2005-2012) have a water leak in the trunk

Solution

1. Preparation

• Gather the necessary tools and parts.
• Ensure the car is parked on a level surface.
• Disconnect the battery if any electrical components are being inspected to prevent short circuits.

2. Inspect and Replace Trunk Seal

• Sub-steps:
  1. Remove any items from the trunk to access the seal easily.
  2. Carefully peel away the old trunk seal from its groove, ensuring not to damage the paint.
  3. Clean the area where the seal was seated using a mild cleaner and cloth to remove debris and old adhesive.
  4. Measure and cut the new trunk seal to size. Ensure the ends meet neatly.
  5. Press the new seal into place, ensuring it is seated evenly without gaps.
• Tools Required: Trim removal tool, utility knife, cleaner, cloth.
• Safety Warnings: Ensure the vehicle is stationary and stable during inspection.

3. Inspect and Reseal Tail Lights

• Sub-steps:
  1. Remove the tail light assembly by unscrewing the retaining screws and gently pulling it out.
  2. Inspect the gasket around the tail light for wear or damage.
  3. Clean the surface where the tail light mounts to the body.
  4. Apply a silicone sealant around the tail light housing to ensure a watertight fit.
  5. Reinstall the tail light assembly and secure it with screws.
• Tools Required: Screwdriver, silicone sealant, cloth.
• Safety Warnings: Avoid applying excessive force to avoid breaking the tail light.

4. Clear Drainage Channels

• Sub-steps:
  1. Locate the drainage channels typically found near the trunk area.
  2. Use compressed air or a flexible wire to clear any blockages in the drainage holes.
  3. Ensure that water can flow freely through these channels by pouring water to test.
• Tools Required: Compressed air, wire coat hanger (if needed).
• Safety Warnings: Wear eye protection when using compressed air.