① The door seal is not tight and water enters: Check whether the door sealing strip is damaged!
② The drainage under the chassis is blocked, causing water to enter the car from below when passing water!
(3) the water tank of the heater in the car leaks, causing antifreeze to leak into the car. Check whether the antifreeze in the water tank is missing!
If the above problems are investigated, the fault point will be found. I'm happy to answer your question. I hope I can help you. Have a nice trip! If there is something wrong with your car, ask the car mechanic. 4S shop professional technician, 10 minutes to solve.