What Causes Car Water Leakage?
2 Answers
Here are the specific reasons for car water leakage: 1. Evaporator drainage: Because the car's air conditioning system has an evaporator installed inside the dashboard, when the air conditioning is turned on (A/C button ON), the surface temperature of the evaporator becomes very low. The moisture in the hot air inside the car will condense on the surface of the evaporator's heat-absorbing fins and is collected by the plastic housing of the evaporator, then drained out of the car through a pipe. 2. Compressor condensation: Sometimes, the exterior of the compressor installed in the engine compartment (low-pressure area) can condense moisture from the air, causing it to drip onto the ground. 3. Lack of insulation foam: If the low-pressure pipes are not wrapped with insulation foam, the surface of the pipes can easily condense moisture from the air, and water droplets often accumulate and drip from the lowest point of the pipes.
With over a decade of auto repair experience, I've found that vehicle water leaks typically stem from just a few common sources. Clogged sunroof drain tubes top the list - when leaves and debris block the drainage ports, rainwater seeps along the A-pillars into the cabin. Deteriorated door seals are another frequent culprit, especially in vehicles over ten years old where hardened rubber allows water intrusion through door gaps. The most troublesome cases involve clogged or detached AC system drain tubes, often causing puddles under the front passenger footwell. Other potential causes include rusted floor pan drain plugs, improperly sealed windshield adhesive post-collision, or deformed sunroof frames. Before rainy season, I recommend simple checks: pour water into the sunroof to test drainage speed, and squeeze door seals to check their flexibility.
