Why do Honda's wheel wells rust?

Answer 1

Many of the civics, especially the older models, have the common rust around the rear wheel well. Many of these rusty civics are located in the north and driven through the winters. There are a couple reasons so many civics are rusting.

First is the condensation that forms on the inside of the car. Think of a glass of ice water sitting outside on a warm summer day. Condensation is going to form on the outside of the glass because it is so warm. I've even seen condensation form on the outside of house windows on a hot humid summer day when the air conditioner is on inside. Same concept with your car. When it is cold and snowy outside, you have the heat cranked up inside your car. This creates condensation, in addition you create more moisture when you are breathing and when you get in your car with snow on your shoes which melts and then evaporates. Cars have vents near the rear to help keep the air flow going through the vehicle, however that is not enough in the civic's case. Also the civic only has this vent on the drivers side below the tail light, not like many vehicles that have them on both sides and even in the door jambs sometimes. This creates condensation build up on the inside of your rear quarter panels. It drips down and collects around the inside of the wheel well. This is how the rust begins where the rear bumper meets the wheel well, the rust starts inside and eats its way through, until you see a tiny bubble or two form on the outside of your fender's paint. Condensation also drips down the front of the wheel well and sits in the inner rocker panel area. Fortunately, the inner rocker panel space has drain holes in the bottom but can still rust. This area is behind the plastic side skirts so you usually wouldn't know if there is rust.

Second cause of rust is the rubber strip Honda puts on the inner fender lip. People rip these off and throw them away because they retain water and road salt. These rubber strips also prevent rock chips which can lead to rust. So instead of taking them off and throwing them away, clean the whole area and inside of the strip & let everything dry, apply body sealer, silicone or similar calk to the inside of the strip and put it back on. Now you have protection from rock strips, and you're keeping the moisture out.