Discovering a water leak in your Mercedes CLA, particularly in the rear passenger footwell, can be concerning. If you’re experiencing damp carpets or unexplained water accumulation in your 2018 Benz CLA, you’re not alone. This issue, while frustrating, can often be diagnosed and resolved with a systematic approach. This guide will walk you through potential causes and troubleshooting steps based on real-world experiences from Mercedes CLA owners.
Identifying the Source of the Leak in Your CLA
One owner of a 2015 Mercedes CLA encountered a similar problem – a wet rear passenger carpet and significant water accumulation. To pinpoint the leak, they undertook a methodical troubleshooting process which can be helpful for 2018 CLA models and similar years. Their approach involved isolating the potential leak areas by using a hose to simulate rain in different locations on the vehicle.
Initially, they ruled out the windshield and side windows by spraying these areas and observing no leaks inside the car. However, when water was directed towards the roof and rear of the vehicle, specifically allowing water to run down the back, a small stream of water was detected entering the cabin. This leak originated from the rear passenger seat sheet metal area, near a hole at the bottom of the sheet metal.
This test suggests that the water intrusion point is likely located on the upper rear section of the car, possibly related to the antenna, rear glass, or the rear glass seal.
Potential Causes of a Rear Footwell Water Leak in a Benz CLA
Based on the troubleshooting steps and community discussions, here are the primary suspects for a water leak in the rear footwell of a Mercedes CLA 2018:
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Rear Glass Seal: The seal around the rear windshield is a common area for leaks to develop over time. Deterioration of this seal can allow water to seep into the car and accumulate in the rear footwell. As referenced in a Mercedes CLA forum, another owner, Bleakfield, resolved a similar issue by replacing the rear glass seal.
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Rear Glass Adhesion: Less commonly, the rear glass itself might not be perfectly bonded to the car body. Gaps in the adhesive can create pathways for water to enter.
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Antenna Base: The antenna, often located on the roof towards the rear of the CLA, is another potential entry point. If the antenna base seal is compromised or loose, water can penetrate the roof and find its way down into the car’s interior.
Community Insight and Further Investigation
Online forums dedicated to Mercedes CLA owners are valuable resources for diagnosing issues like water leaks. The experience shared by the CLA owner and the reference to Bleakfield’s similar problem highlight the rear glass seal as a likely culprit in rear footwell leaks.
If you are experiencing a wet rear footwell in your Benz Cla 2018, replicating the hose test described can be a helpful first step in narrowing down the leak’s location. Carefully examine the rear glass seal, antenna base, and surrounding areas for any signs of damage or gaps. While this guide offers potential causes, professional diagnosis by a qualified Mercedes-Benz technician is recommended to accurately identify and repair the water leak in your CLA.
