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Discussion Starter · #1 ·
I had some water leaking through my trunk which causes mold and is leading to me refurbishing my trunk. As of this week I just began the process and am posting a complete down to basics guide if anyone decides to follow my footsteps. The pictures right below this text are of the mold on the cardboard-ish material under the carpet.


Waterproofing Guide

Tools and Materials Required
  • Caulking Gun
  • 10mm socket(to remove bumper)
  • Silicone water/proofer(make sure it can adhere to metal and plastic)
  • panel clips(because I always break mine)


Water leaks in the trunk can cause water to pool up in the spare tire compartment and eventually lead to mold and rust in the trunk compartment. After finding a pool of water in my spare tire compartment and having mold grow under my trunk mat I decided to help make a guide to help solve and avoid this problem for anyone else.


Some of us might not have a big pool of water to inform us of trunk leaks, but if you trunk carpet feels damp it could be signs of a leak. I’d advise to feel around the edges of the mat especially on the left side near the taillights because there is a vent which members including myself have had a leak.

Finding the Leaks

If you think you have a leak than the best way to find out where it is coming from is to have a friend hose your car with high power, but not high enough to harm paint. While your friend is hosing the car you need to be inside the trunk with a flashlight looking for running water. So just fold down the back seats and get in there.

Possible Leak Locations

• Tail lights (The picture is post waterproofing)
• Spoiler holes
• Left side vent(It can be found behind the liner near the taillight on the driver’s side)

Fixing the Leaks

There many different ways you could solve this problem depending on where the leak is. For the spoiler you could get a gasket to fit around the holes, but I used silicone caulking and has been successful thus far. Although for the taillights I used a different water proofer just to test it out and worked well but it functions the same. Just take the caulking gun and bead around the edges of the leaks. For the taillights I used latex gloves and pushed the silicone into the cracks than applied a second layer on the inside. For the spoiler I just used the silicone and make a bead around the perimeter and wiped off the excess after being tightened.

The side vents I’d highly recommend sealing the inside and the outside just for safety's sake. For the outside, take off the bumper and bead around the edges and use disposable gloves(silicone is annoying to wash off.) to make a slope on the top of the vents with the silicone to allow water to slide down if any gets in the area.

Before - This car was rear ended, I do not believe everyone's will be as bad, but many members claim this to cause leaks.

After - notice how the silicone makes a ski slope. It is important to not allow water to pool up around the cracks.

Once you seal all the spots, be sure to allow everything to dry, if you have to drive and have a sub in your car I would recommend not using it because the vibrations could ruin the seals until they are set in.

work in progress


Since I suffered from the mold program earlier the trunk was cleaned, the carpet and the support were put to the side because it is easier to trace them than to "wing it." This guide is a work in progress, but I'm install a sub and amp into the trunk and am going to do some serious overhauls after I was so damn impress with one of the members trunks which I have pictured below.

Tools/Materials (will vary)

Making the Support

First and most importantly is do not throw out your old support. Not yet at least. Salvage the old plastic brackets because they will be going on the new piece. Trace the pattern of the old support onto a piece of plywood. (you can use other material, but I wanted something sturdy) Using a sawsall or a jig-saw follow the pattern you drew. Now if you are like me, you're finished product is not exactly how you traced it. You can use the belt sander to shred the edges to make them fit the lines, than you can round the edges to prevent them from poking at things.

Once you get the design down you need to match up the bracket locations from the old support onto the new one and drill two hole for a nut and bolt to slide through and hold them together. I did not use my old foam blocks because the mold, so I cut blocks off the end of my mattress topper. They were about the same size. Id recommend using a strong adhesive to secure them in place and let it dry before putting it back in.

coming soon :D

Premium Member
39,133 Posts
Good luck pimp.

575 Posts
I've had a pool of water in my spare well for weeks then let my car sit outside idle for 3 years...and didn't get THAT much mold. Daymn son.

But nice job fixin it up.
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