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Hi, I need helping ideas with leaking water in the trunk. I discovered in my newly acquired 2016 E350, after a short car wash, or quick rain, there was water leak in the trunk floor, the area around spare tire, aux battery and fuses box!. Interestingly, the trunk's carpet is totally dried, indicated the water leaked straight down to the trunk floor, not through the carpet. I already visual inspected the seals, general areas.... and everything seem normal. Anybody has any ideal where the leak might have come from? where to check?. My family member bought this car brand new. After few years, there was a recall for trunk leak, so dealer installed a "seal" directly at the bottom of the window! (never seen anything like that before). Now since Im taking over the car, I started to pay attention... and despite the "fix", water still passed into the trunk, even with a short car wash!.
I also have a 2008 W211, which suffered a notorious trunk leak. There are many discussions about this issue on the forum. I already replaced the tail lights gasket seal, siliconed all the holes, opening on the trunk lid, yet it still leaked!. However, when it leaked, the trunk carpet was all wet. Im so frustrate Mercedes couldnt design a car without leaking trunk generation after generation. Even the cheapest chinese cars dont have this problem....
Hi, I need helping ideas with leaking water in the trunk. I discovered in my newly acquired 2016 E350, after a short car wash, or quick rain, there was water leak in the trunk floor, the area around spare tire, aux battery and fuses box!. Interestingly, the trunk's carpet is totally dried, indicated the water leaked straight down to the trunk floor, not through the carpet. I already visual inspected the seals, general areas.... and everything seem normal. Anybody has any ideal where the leak might have come from? where to check?. My family member bought this car brand new. After few years, there was a recall for trunk leak, so dealer installed a "seal" directly at the bottom of the window! (never seen anything like that before). Now since Im taking over the car, I started to pay attention... and despite the "fix", water still passed into the trunk, even with a short car wash!.
I also have a 2008 W211, which suffered a notorious trunk leak. There are many discussions about this issue on the forum. I already replaced the tail lights gasket seal, siliconed all the holes, opening on the trunk lid, yet it still leaked!. However, when it leaked, the trunk carpet was all wet. Im so frustrate Mercedes couldnt design a car without leaking trunk generation after generation. Even the cheapest chinese cars dont have this problem....
These excellent cars feature a collection of engineering issues refined year after year
The sunroof discharge has 4 plastic pipes that shrink and pull-off...
Discharge hoses use a rubber nozzle that conveniently glues itself shut to overflow...
The water discharge channel area surrounding the trunk lead seal features a plastic cover fastened by rubber pins that are drilled straight into trunk area...
You describe an entry point that seems low-down not up-high...
Remove the side carpeting for inspection.
Use paper towel as markers of rain entry...
🤞
Last edited by CaliBenzDriver; Dec 25, 2025 at 05:48 PM.
My W204 was leaking from the trim fasteners. Verified by inspecting the underside in the trunk right after a rain storm.
If i were looking for the source of a leak i would pour water starting at the lowest point, inspect, then if dry move up to the next spot. Thats how I used to test windows for leaks, use a garden hose and direct the water along the sills for a few minutes then looking inside for signs of water, if nothing them move up the jambs, then head.
testing sliding sunroof drains is easy and just pour a cup of water and see if it drains or gets backed up. Then look for water dripping out the bottom onto the ground.
There are also some vents (50) on the sides of the trunk area. Could always check the area around the vents inside for water. I dont see this being the cause but worth a look.
DO SILICON RTV every single connector you see outside cabin area:
-A- Rear bumper area (radars, TPMS!)
-B- Front bumper area (A/C pressure Sw! + side harness!)
-C- Engine bay area sensors
The connector waterproofing task has low-priority It's a simple step towards basic reliability.
Compromised connectors a serious PITA to repair once oxidized - Contact tiny springiness is compromised regardless of being cleaned and sealed.
CarCareNut uses the word JUNK to name this 2023 Lexus connector downgraded to guarantee issue.
Last edited by CaliBenzDriver; Dec 25, 2025 at 08:34 PM.
Thanks for the ideas. I was hoping for a quick solution. Looks like I will have to do water test to identify the leaking point. On the W211, I already replaced the plastic water channels on the L and R side of the trunk; replaced all the rubber pins, plastic clips. I even silicon these whole area, replace tail light gasket, yet it still leaked!. I did what ever I could thought of, proofing the whole trunk, yet it still leaked!. On the W211 forums, it was a recurring issue, and there was no absolute fix for it....
Thanks for the ideas. I was hoping for a quick solution. Looks like I will have to do water test to identify the leaking point. On the W211, I already replaced the plastic water channels on the L and R side of the trunk; replaced all the rubber pins, plastic clips. I even silicon these whole area, replace tail light gasket, yet it still leaked!. I did what ever I could thought of, proofing the whole trunk, yet it still leaked!. On the W211 forums, it was a recurring issue, and there was no absolute fix for it....
You should apply all your W211 expertise to fixing this W212 in hope it's using a shared design issues you know.
I guess the rear windshield seam should also be tested here
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
