If you open your trunk and find the carpet soaked after a rainy day, that’s more than just an inconvenience—it’s a sign that water is getting into your car where it shouldn’t be. A wet trunk doesn’t just ruin whatever you’re storing back there. Over time, it can lead to mold, mildew, and corrosion that damages your vehicle’s structure and electrical components.
Water intrusion in the trunk area is surprisingly common, especially in older vehicles or those that have been through body repairs. The good news is that most leaks can be tracked down and fixed without major work—if you know where to look.
Where the Water Is Coming From
One of the most common sources of trunk leaks is a worn or damaged trunk seal. This rubber gasket surrounds the edge of the trunk and is designed to keep water out, but age, heat, and pressure can cause it to crack, flatten, or come loose.
Another culprit? Tail light assemblies. If the seals around your tail lights are old or improperly installed, rainwater can run down into the trunk behind the plastic trim. It often goes unnoticed until the carpet is soaked or the spare tire well starts collecting water.
Cracks or gaps in the body seams, welds, or trunk lid channels can also let water in, especially if the car has been rear-ended or repainted. And don’t forget about clogged or misrouted drain tubes—many vehicles have them hidden near the trunk hinges or under trim panels to direct water away from seals. When they get blocked, water backs up and ends up inside the trunk instead.
How to Tell If It’s Been Leaking for a While
If the leak has been going on for more than a few days, you might notice a musty smell when you open the trunk. The carpet could feel heavy, spongy, or even show signs of discoloration or mold growth. In more serious cases, rust may start to form underneath the carpet or around the spare tire area.
Electronics stored in the trunk, like amplifier modules or battery systems in hybrid vehicles, can also be at risk if moisture sits around them too long.
If you're unsure where the water is coming from, a good trick is to dry everything out, then run a hose over the trunk while checking inside with a flashlight. You’ll often see small drips forming along seams or trickling down from hidden spots.
Fixing a Leak Now Saves Bigger Repairs Later
It might seem like a minor issue—but letting water sit inside your trunk can cause bigger problems than just damp carpet. Trapped moisture encourages rust to form, and once corrosion begins in the seams or floor pan, it can spread fast and become much harder (and more expensive) to repair.
Plus, once mold takes hold in carpet padding or trim, it’s difficult to fully remove the smell and spores. That affects the overall air quality inside your car and may trigger allergies or respiratory irritation.
What to Expect From Ming’s Auto Repair
Fixing a trunk leak starts with removing the trunk trim to inspect the seal, tail light housings, and weld seams. We may use a smoke machine or leak detection dye to track the water path if the source isn’t immediately obvious.
From there, we might replace the trunk seal, reseal the tail lights, or repair body seams with fresh sealant. If drain tubes are involved, they’ll be cleared and rerouted properly to keep future water away from the interior.
In cases where moisture has been sitting for a while, the technician will dry and clean the affected carpet and check underneath for signs of rust or mold that need to be treated.
Tired of dealing with a soggy trunk every time it rains? Bring your vehicle to Ming’s Auto Repair in Allston, MA. Our team will track down the source of the leak, fix it for good, and make sure your trunk stays clean and dry.