What is the Difference Between Rust from Flood-Damaged Cars and Natural Rust?
3 Answers
Flood-damaged cars are mostly affected by turbid rainwater, which contains harmful gases, impurities, and acidic substances from the atmosphere, accelerating vehicle corrosion. The entry of turbid rainwater into the car causes severe corrosion. In contrast, natural rust develops more slowly. Below is relevant information: 1. Flood-damaged cars: As the name suggests, these are vehicles that have been submerged in water. They are categorized into three types based on the severity of damage: the first type involves water depth exceeding the wheels and entering the interior; the second type involves water depth surpassing the dashboard; the third type involves water rising above the car roof. 2. Waterlogged cars: This refers to vehicles driven on low-lying, waterlogged roads, passing through water. This usually occurs during rainy weather in low-lying areas with inadequate drainage systems leading to water accumulation on the road.
I've been burned buying used cars before - water-damaged rust is terrifying. Regular rust is like a surface wound, maybe just some bubbling paint. But flood cars have internal damage - water seeps into electrical connectors causing electrochemical corrosion, aluminum parts turn to mush, and moldy rust flakes form in frame corners. The scariest part? When mechanics lift the carpet to see reddish-brown fluff growing from steel panel seams, they just shake their heads saying this rust eats from inside out. Now I get suspicious seeing cars with abnormally clean undercarriages - could be flood cars with deliberately polished rust cover-ups.
From an auto mechanic's perspective, water-induced rust differs entirely from ordinary rust marks. Natural rust typically starts at exposed areas like door edges and wheel arches, appearing as scattered sesame seed-like spots. Flood-damaged cars exhibit concentrated rust around wiring harness connectors beneath carpets or in hidden corners like seatbelt anchor points—removing interior panels reveals widespread rust patches. More critically, electronic module pins develop green corrosion, which can even disable ABS pumps. That's why used car buyers mustn't skip inspecting seat rail screws for salt crystallization—it's worth removing a couple to check.
