Will a cracked rear bumper leak when it rains?
4 Answers
If the rear bumper is cracked, it will not leak when it rains. Here is some relevant information: 1. Car bumper: The car bumper is a safety device that absorbs and mitigates external impacts, protecting the front and rear parts of the vehicle body. It can provide a cushioning effect when the car or driver is subjected to collision forces. With the continuous development of the automotive industry, engineering plastics are now widely used in the automotive field. Nowadays, the front and rear bumpers of cars are made of plastic, which makes the vehicle body shape more harmonious and unified while also reducing the weight of the vehicle. 2. Repair: Whether the bumper needs to be repaired or replaced depends on the extent of the damage. If the internal support structure of the bumper is severely damaged or cracked, it generally requires replacement. When replacing the bumper, it is best to choose an original equipment manufacturer (OEM) part. Although the price is relatively higher, the quality of OEM bumpers is better than that of aftermarket ones.
Last time I reversed my car, I accidentally cracked the rear bumper and didn’t pay much attention at first. However, during heavy rain, I noticed the trunk was soaking wet. Actually, a cracked rear bumper won’t directly leak into the cabin, but rainwater can seep through the crack into the inner side of the bumper, where there are many metal brackets and the spare tire well. If the water can’t drain out, it can cause the car frame to rust within months and even make the soundproofing mat at the bottom of the trunk moldy. Later, I spent 500 yuan to repair the bumper, and the mechanic also helped me clean out the waterlogged cavities. My advice is not to delay—the sooner you fix it, the more money you’ll save.
From a repair perspective, regarding the issue of a cracked rear bumper, the plastic shell itself breaking won't directly cause water leakage into the vehicle interior. However, rainwater can enter the internal cavity through the crack. If water accumulates over time, it may corrode the crash beam. More seriously, moisture can seep into the trunk floor through the spare tire well ventilation holes, and prolonged dampness can easily lead to odor buildup. Last week, we encountered a car owner who had to spend thousands replacing sound insulation materials due to this issue. It's recommended to temporarily seal the crack with waterproof tape immediately and then have it professionally repaired. Don't wait until rust develops to address it.
When my little Polo's rear bumper was cracked, I specifically asked an experienced mechanic. He said rainwater usually seeps in through three pathways: first, water accumulation in the inner cavity of the bumper backflows into the taillight gaps; second, the aging trunk seal combined with water accumulation creates a siphon effect; third, water accumulation seeps in by overflowing the frame welds. He advised me to regularly open the side panels of the trunk to check the humidity of the soundproofing cotton and address any dampness immediately. Now I check it every month, saving money on major repairs later.
