How To Fix Leaky Truck Slider Windows

Older truck models have slider windows just behind the rear seats. The problem with these windows is that they have a tendency to leak when it’s raining or when you’re cleaning the truck.

Water gets into the vehicle and leaves the seats soaking wet. Some of the water gets into the carpet and other parts of the cabin, which then leads to mold growth and a musty smell. Thankfully, you can fix leaky truck slider windows from the comfort of your home.

Clearing drainage channels

If the drainage channel is clogged or isn’t draining properly for some reason, it can cause water to build up and leak into the truck’s cabin. Clearing the drains will fix the leaking problem. For this, you need noise pliers, a flathead screwdriver, and a can of compressed air.

1. Open the sliding window completely from the outside of the truck.

2. Pull the rubber gasket apart on both sides. You should see a drainage channel between its two pieces.

3. Use a flashlight and check for visible signs of blockage, such as pine needles or pebbles.

4. Use pliers to remove any obvious blockages. Blow it with compressed air to remove any dust or debris that’s left behind on the drainage channel.

5. Get inside the truck and look for the interior drain holes. You can find them in front of the sliding glass, on the two bottom corners. These drains are also prone to clogging and can cause the sliding window to leak.

6. Close the sliding windows completely to release the tension on one side of the automatic slider cable. To trigger the mechanism, you can use a flathead screwdriver to gently nudge the slider cable mount towards the far side.

7. Next, use compressed air to clear the drainage hole. It should remove all dust and buildup that’s been preventing water from flowing and condensing.

8. Replace the slider cable mount.

9. Open the sliding window completely, this time to release the tension on the opposite side of the automatic slider cable. Use the flathead screwdriver to trigger the mechanism.

10. Repeat steps 7 and 8 on this side of the sliding window.

Rerouting the water away from the sliding window

Clearing the drainage channels only provides a temporary solution for leaky slider windows. If you want a more long-term solution, you should add a rubber channel that will divert water towards the left and right sides of the truck.

We recommend getting high-quality 5/8″ tall black drip rail molding and a weather-resistant rubber with 3M adhesive. The molding should span the entire width of the rear window and not just the slider. You also need rubbing alcohol, a rag, and scissors for this fix.

1. Soak the rag with alcohol and use it to clean the glass surface where the rubber molding will be attached. After cleaning, wait for the surface to dry.

2. Cut the molding to your desired length. Make sure that it is centered and aligned with the antenna, your brake light, or the vertical seal of the glass window.

3. Stick the molding on the window. Press it firmly along the channel so it sticks properly.