What to Do When a Lot of Water Gets Inside the Car?
4 Answers
First, remove the spark plugs and use the starter to crank the engine, expelling any water that has entered the engine internals. Use compressed air to clean the electrical components and connectors inside the engine compartment to prevent short circuits. Open the rubber seals located under the vehicle chassis to drain the accumulated water from the cabin. Remove highly absorbent interior materials like floor mats and place them in a spacious area to facilitate water evaporation.
I once forgot to close the car window on a rainy day, and water accumulated up to the depth of the floor mats. Whatever you do, don't start the car immediately. If the water level reaches under the seats, call your insurance company directly for a tow truck. Otherwise, repairing a waterlogged engine or transmission will break your heart. Remember to have the repair shop remove all the car carpets and soundproofing cotton to sun-dry them for two or three days, or the musty smell will haunt you forever. Also, check if the sunroof drainage holes are blocked—if they're clogged, water can leak in even with the windows closed. Finally, remember to ventilate and dry the car thoroughly before washing it, or the remaining mud stains can corrode the wiring.
Last time during the humid season, the car floor was full of condensation. I figured out a set of procedures: First, immediately disconnect the battery negative terminal to avoid short circuits, and use a towel to soak up any obvious standing water. You must remove the seats to thoroughly dry the carpet, otherwise moisture trapped underneath can rot the frame. Pay special attention to the spare tire well in the trunk, as it's the most prone to water accumulation and corrosion. If you have a vacuum cleaner, it's very convenient to directly suck water near the drainage holes, but never use the heater to dry it out - moisture getting into the dashboard would cause bigger problems. After air-drying for three days, be sure to thoroughly inspect all wiring connectors, especially the wire harness connectors near the door sills which are very prone to developing green corrosion.
Avoid parking in low-lying areas during the rainy season. My neighbor's Audi A6 had its ECU damaged by water last time. Take photos immediately for insurance evidence if water enters the car, and emphasize it was flooded while parked to qualify for claims. Repair shops will remove all interior parts for drying, but you must supervise to prevent them from cutting corners. Moldy carpeting must be completely replaced, or it will cause endless trouble. I recommend replacing all four door seal strips while you're at it - aged and cracked seals are a major cause of water leakage. Oh, and don't forget to clean the AC filter - it's prone to bacterial growth after being soaked.
