How to Fix GMC Leaking Sunroof

A sunroof is a nifty feature on your car as long as it's working properly, but one that is leaking can make a mess inside the vehicle. There are a few reasons that a sunroof can be leaking, and most of the problems are easy to fix.

GMC Sunroof

Your sunroof has drain tubes that are necessary to keep the water from leaking inside your vehicle, and the first step to fixing your leak is to clean out the drains. There are two methods for doing this; you can use compressed air or use a metal wire.

  • Using Air to Clean the Tubes

Just inside the rubber seal, there is a sunroof trough. You need to clean it out from time to time. Use a cloth to wipe it clean and remove any debris that you see on the edges or on the seals.

Find the drain tubes that are located near the corner under the seal.

Use compressed air to blast through the tubes. This should clear out any dirt, leaves or other debris that might be clogging up the tubes. You should do this regularly to keep the water from building up or leaking.

  • Using Metal Wires

A flexible wire like a bicycle brake line can be used to snake through the drain tubes. Do this for all the drain tubes. Insert the metal into the tube, and twist it back and forth while continuing to push it in further. You should find no resistance, and it will push all the dirt out as you push it in further.

If you get resistance, stop and remove the tube. You can damage the drain by trying to force the wire through it. You may need to get your local GMC dealership to clean the tubes.

  1. Clean the drain tubes.
  2. Pour water over the glass to check for leaks inside the vehicle.
  3. If you have leaks, then you need to fix the seal. If you do not see any leaks, then you have successfully fixed the leaking.

Fixing the Seal

  1. Check the sunroof seal for cracking or rough edges. Since they are seals, they are subject to drying out just like any rubber part.
  2. Check around the seal for mold or beads of water that can indicate that the seal has lost its shape. A buildup of water can create small holes in the seal.
  3. Get a can of black liquid electrical tape and brush it onto the worn parts on the seal. Use a thick layer and cover it well. It will dry to create a waterproof layer that protects the seal. Press it down around the seal. Follow the manufacturer’s instructions for application and drying times.
  4. Shut the sunroof and give it the water test again. Poor water over it, and check for leaks inside the vehicle.

If you continue to have problems, you may need the professional help from your local GMC dealership or you may need a new sunroof due to factory flaws or other faults.