Where is the water leaking under the cabin?
2 Answers
After ruling out human factors, if water is still dripping under the car cabin, you should check the car's drainage outlets. Here is the relevant information: Rainwater entering through unclosed windows: After parking, if the owner fails to ensure the windows are tightly closed, rainwater can seep into various parts of the car through the unclosed windows. Over time, water will accumulate under the cabin. Issues with drainage outlets: After eliminating human factors, if water is still present under the cabin, inspect the car's drainage outlets. There are four drainage outlets in total—the front two are for sunroof drainage, and the rear two are for draining water flowing on the car.
There is water under the cabin, and I have encountered this issue several times. The most common cause is a clogged condensate drain pipe from the air conditioning. When you turn on the AC in summer, it's normal for water to drain from there, but if dust or leaves block the pipe, the water can backflow into the car. Another possibility is a leaking heater core, especially in winter—if antifreeze leaks out, it will wet the floor and has a slightly sweet smell, which requires attention. Aging door seals could also be the culprit, allowing rainwater to seep through the gaps, particularly in older cars where the rubber has hardened. If the sunroof drain is clogged, rainwater can back up into the headliner and flow down under the cabin. Additionally, cracked windshield sealant may let water in during heavy rain. For solutions, regularly clean the drain pipes and seals—unclog them when blocked—it's cost-effective and gives peace of mind.
