Auto body repair & detailing: Rain water leaking up into car on floor., mitsubishi galant, water leaks

Question
Hi William,

I have a 2000 Mitsubishi Galant.  I brought it used and I think it was in a rear-end accident before I owned the car.
Whenever it rains, a puddle of water collects on the driver side floor.  The water comes up through a hole in the carpet.  I don't know where the water is coming in from.
Do you know a place where water could come in and travel or collect under the body of the car ?
And, would it be a good idea to put a hole in the floor of the car so the water have somewhere to flow out of the car ?  Would this result in rust ?

Answer
Hello! If the water enters when the car is stationary, it's a gravity leak, coming in from the top down. Water leaks are pesky, and hard to pin point without taking out all of the carpet and seats. Drilling a hole under the driver floor pan will help, but the car will sop water when it's moving in the rain. It's a temporary fix, and all the water will cause rust, eventually. If you want to track it down, remove the front seats and pull back the carpet as far as you can. Look for telltale dirt trails leading from the upper parts of the cowl down. It may lead to an obvious cause. Then, Have a helper spray a hose on the body on the side it accumulates water on. Close the door. Start low, and be patient, using a rain-like spray of water. Slowly move up the body, until you reach the highest point of the roof. If it doesn't show up, the water may be coming in from the rear, gravitating to the front. Pull the rear seat and remove the carpet, and look for more telltale dirt trails. Once again have a helper spray the rear body, around the glass. doors, and inside the wheel house. Expect leaks around seals, seams in the body, and around glass. A pinhole in a seam will act as a siphon, and draw an amazing amount of water into a vehicle. If this sounds like its beyond your capability, take it to the dealership. They can help. Bill