Not your typical trunk leak

[Honcho]

After a torrential storm here on Long Island, I opened my trunk to find that it was sopping wet! A quick search on Prime revealed that the major culprit is the taillight gasket. To confirm, I did the cup of water/flashlight pour test and it was bone dry. To confirm, I blasted the lights with a garden hose and re-checked. Again, bone dry around the taillight holes on the inside of the trunk. Totally confused, I closed the trunk and simulated a rain shower with the hose on the trunk. When I opened the lid, my gf spotted a wet mark on the inside of the trunk weatherstrip.To make sure it wasn't a drip from the opening lid, we dried the area and re-tested with the hose. Sure enough there was a wet mark, and water had pooled on the inside of the gasket line. The strange part was that the weatherstrip appeared to be in good order - do dents or tears. Yet, the water was getting in somehow.

Pulling up the weatherstrip, we found this:

The red arrow is pointing to where the metal frame was bowed out. There was water trapped and pooled on both sides of this bend. The blue arrow is pointing to where the water was pooling when the trunk was closed. When full enough, it would drip down to the right and pour into the trunk - exactly where the wettest part was.

Turning over the weatherstrip, we saw this:

The bend in the metal divider had splayed open the slot in the weatherstrip, indicated by the red arrow. The water was forcing itself up through this opening. We cleaned out the area, sopped up the water and tried to force the weatherstrip back down, but found the bowed out metal wouldn't allow the strip to seat all the way down. As a final test/safety measure, we stuffed some paper towels along the inside of the strip where it was leaking and closed the trunk. The was another rain storm last night and sure enough, when we opened the trunk this morning, the paper towel was soaked.

So now my question. Even if I buy a new weatherstrip, I think this bent metal divider will cause the same problem. Should I take a pair of channel locks and try to bend it back straight? Has anyone else run into this issue?

 

[Jett]

I would definitely try and straighten out the metal. Sounds like the weatherstripping isn't the problem at all. Fix the metal and rebed your old weatherstripping, assuming it didn't get messed up from prying it up. Good job troubleshooting this, by the way.

Your girlfriend helps you work on your car? Does she have a twin sister who is available? :smile:If she had a well-stocked toolbox, that would also be helpful. :smile: Send picture of toolbox.:smile:

 

[Honcho]

Thanks Jett, I'll probably try that, but wanted to check with the gurus before doing something stupid to my new NSX. :biggrin:

Nope, gf does not have a sister lol. She is the best - always likes to help me with the car! :smile:

 

[Jett]

...wanted to check with the gurus...

You have mistaken me for someone who knows what he is talking about.

 

[Ben]

I would check the taillight lenses also. It looks like your taillight lenses are separating from the taillight body. It's starting to happen more and more on the earlier cars. That can also let moisture and water in. I found that to be the source of a trunk leak before.

 

[Honcho]

You're right Ben, but we checked the back of the light housings during our water tests and they remained bone dry. Still, I'm getting some vapor/condensate inside the lenses. I'll probably drill some weepholes per some of the other members here. Not visible and they will solve the problem once and for all, as opposed to me trying to pry open and re-seal the light housing, which will likely result in me having to buy a new set lol :biggrin:

 

[Ben]

I would resolve the separating lens issue regardless, because it can let moisture into the trunk, which condenses inside, and is very hard to dry on it's own. It's even worse if you live in a humid environment. Over time, mold will form in the trunk and carpets. Once it gets to that stage, you have to strip the trunk the painted aluminum shell, power wash it with strong detergent several times, let it air out for weeks, and replace all the carpets to get rid of the smell. I know this firsthand from ignoring the condensation inside the taillight lenses. Ultimately, in addition to everything above, I had to replace the entire trunk carpet set, both taillights, and CD Changer. The CD Changer, tool kit, and power antenna also had corrosion on it.

 

[Honcho]

Wow Ben that's enough to convince me to take care of it. To follow up, we had another rain storm and my repair worked. No moisture in the trunk! Jett (and my gf lol) was right - the bend wasn't letting the gasket seat all the way down. Now that it is, no more leak.