
Here are the functions of undercoating: 1. Anti-corrosion for the chassis: Northern regions have rain and snow weather, while southern regions have rainy and foggy weather. Moisture naturally corrodes the car's chassis over time, and residual wastewater after car washing can also cause certain damage. However, undercoating forms a protective film on the bottom of the car. 2. Protection against stone impacts: While driving, vehicles often kick up small stones, and the impact force of these stones on the car's underbody is proportional to the vehicle's speed. 3. Thermal insulation: When the air conditioning is turned on, the cold air inside the car sinks, while the hot air outside rises, eventually gathering near the car's chassis for exchange. Therefore, the protective effect of the car's chassis directly determines the vehicle's cooling efficiency. 4. Prevention of underbody scraping: Each layer of undercoating can be 1.2-2.5 mm thick, reducing damage when the car's bottom is scraped by protruding objects. 5. Savings on costs and car value preservation: The chassis supports the car's four major systems, so protecting the chassis means protecting these systems, saving a series of maintenance costs. Typically, rust starts to appear on new cars after about three years of use. Correspondingly, the better a vehicle is maintained, the higher its value. After some time of driving, whether for personal use or preparing to trade in for a new car, a vehicle that has undergone undercoating protection (especially with quality assurance from reputable large companies) will undoubtedly have higher value.

As a veteran driver who has been driving in rainy regions for years, I find underbody coating quite useful. The mud splashes and de-icing agents on rainy days can corrode the chassis, and unprotected cars may develop rust spots within three to five years. My car still has a clean underbody after five years of coating application when lifted during the last . This rubber coating acts like a raincoat against corrosive substances and also reduces noise from small stone impacts. However, don't go for cheap options - my friend used inferior materials that cracked and peeled off within two months. It's best to choose imported rubber-based materials. For vehicles frequently driving on rough rural roads, the anti-scratch effect of underbody coating becomes even more noticeable.

I've been working in an auto repair shop for nearly ten years and have personally handled chassis issues on over a thousand vehicles. Chassis armor is indeed crucial for rust prevention, especially on roads where de-icing agents are used in northern regions. Unprotected vehicles often start rusting after three years, requiring entire steel panels to be cut out and replaced during repairs. Even after eight years of use, vehicles with proper armor usually only show minor rust spots. During application, pay special attention to corners and edges where coverage is most likely to be missed - fuel tanks and exhaust pipes require high-temperature resistant materials. While new vehicles come with thin factory-applied rustproofing, this original protection is far from adequate. I recommend applying professional-grade armor within six months of purchase.

Last year when I bought a new car, I specifically had the underbody coated with anti-rust protection. After one year of use, I feel it was worth every penny. With city sprinkler trucks spraying water daily, my previous car's undercarriage always had white salt stains. Now with a 3mm thick rubberized coating, I can clearly see dirty water sliding right off during car washes, unlike before when it would seep into crevices. The manufacturer this material also absorbs vibration noise, and indeed there's less tire noise on the highway. I recommend applying this protection as soon as you get a new car - it's pointless if the underbody of an old car already has rust. I chose an environmentally friendly resin type that's odorless and comes with a lifetime warranty.

Living by the sea, I can tell you that undercoating is a lifesaver. The salt-laden sea breeze corrodes the chassis at an unbelievable rate—my first two cars had rusted-through chassis in less than five years. My current car has undercoating, and after six years, a lift inspection shows the metal parts still shining. I make sure to rinse the chassis during weekly car washes, and the coating completely blocks the saltwater. I recommend choosing polyurethane material, as it offers better corrosion resistance than ordinary asphalt coatings. Although it cost over 2,000 yuan, it’s more economical in the long run by saving on major repair costs later.

People who work on sites are particularly sensitive to underbody protection. There are often large rocks and debris on the site, and without armor, the underbody becomes pitted and dented within three months. I spray armor on every pickup truck I own—a two-centimeter-thick rubber layer can withstand scrapes from steel bars. Last time I hit the underbody while crossing a muddy pit, the armor lost a chunk, but the frame remained intact. Modified off-road vehicles should have double-layer protection, with the second layer made of high-elasticity resin to prevent stone chips. Although it adds weight, protecting fuel lines and wiring is crucial. Checking the integrity of the armor before long trips has become part of my routine.


