The recent floods after Storm No. 3 (Yagi) caused extensive damage to several provinces in the North, with major cities such as Hanoi, Thai Nguyen, Tuyen Quang, Bac Giang, … having a large number of cars submerged in the floodwaters.

Flooding is always the number one enemy of automobiles as modern cars have a lot of electronic systems and lubricated components that should not come into contact with water…


Countless cars parked in an apartment building in Thai Nguyen are surrounded by murky floodwaters. Photo: Bao Khanh

Therefore, after being flooded, cars need to be rescued immediately for repairs. The following are the details that car owners need to pay special attention to for smooth and effective repairs.

1. Braking System

Car brakes are an important safety feature. Even a day of immersion in water can immediately affect the braking system, especially in severely flooded areas like Thai Nguyen, where cars are submerged for up to a week.

According to Mr. Huynh Trong Nhan, owner of Trong Nhan garage (Vinh Tuy, Hanoi), most cars are parked with the handbrake engaged, using the force from the cable to pull the brake shoe or the piston to press against the brake pad to keep the car stationary. Soaking in water, especially floodwater with a lot of impurities, accelerates oxidation at the contact points compared to a normal humid air environment.

Therefore, as soon as the car is out of the flood, clean the mud and debris, and then disassemble the brake mechanism, including both the foot brake and the handbrake, to clean and maintain them. This will prevent the brake pads from seizing up against the disc or becoming severely corroded.

2. Electrical System

If the floodwater enters the car’s floor, it is mandatory to remove and inspect the entire floor and the underlying wiring. In the storm and flood, many cars are submerged up to the roof.


Electrical system diagram of a BMW sedan. Photo: Wikipedia

Cars that have been submerged in floodwaters for a long time will likely have water damage to their electronic boards and wiring, causing malfunctions or unstable operation. These components should be thoroughly inspected and replaced if necessary.

Additionally, water may have entered the fuse box, causing damage, so it is important to check this component next if the car is experiencing any issues.

3. Replace Lubricants and Greases

On automobiles, lubricants and greases are used in various components such as the engine, transmission, power steering, etc., while greases are used in components like bearings, suspension, and steering systems.


It is recommended to replace all lubricants and greases after dealing with flood-affected cars. Photo: Motul

When a car is submerged in floodwaters, the lubricants and greases in these components are likely to be contaminated, diluted, and lose their lubricating properties. Continuing to use them without replacement can lead to reduced lubrication quality or complete loss of lubrication, resulting in damage to the vehicle’s components.

4. Engine-Related Components

In automobiles, components like fuel injectors, intake manifolds, spark plugs, high-tension wires, and air filters directly impact the vehicle’s performance. Proper maintenance of these components optimizes engine performance, fuel economy, and overall smoothness of the vehicle. Therefore, it is crucial to thoroughly clean these parts with specialized solutions after the car has been flooded.

Next, the starter and alternator are durable components that rarely malfunction. However, if submerged in floodwaters, oxidation and water intrusion can cause damage. It is advisable to prioritize checking and replacing these parts to avoid the risk of being stranded.


Location of the drive belt connected to the camshaft on a car. Photo: Autocar

Finally, the drive belt affects the operation of components such as the camshaft and water pump. Typically, this belt is very durable, with a replacement interval of 80,000-120,000 km depending on the vehicle. However, prolonged immersion in floodwaters with debris can affect its structure and reduce its durability, making it prone to breakage during operation.

Replacing the drive belt is still more economical than the potential risk of the car breaking down due to engine failure, or the belt snapping and damaging other components in the engine compartment.

5. Air Filters

As the name suggests, air filters are designed to filter out dirt and debris, ensuring cleaner air enters the car, such as the engine air filter and the air conditioning filter.


A dirty or mud-caked air filter loses its filtering ability. Photo: Carpartsp>

Automotive experts recommend replacing air filters if the car has been flooded for an extended period, especially in floods with high levels of mud and debris. The reason is that the fabric or paper layers that make up the air filter will become caked with mud and lose their filtering ability. Cleaning and drying the filter may not ensure its effectiveness.

Moreover, air filters are relatively inexpensive, so it is not worth compromising on this component to avoid potential engine damage or health risks.

According to VNN

Frequently asked questions

First, do not attempt to start the car as this could cause further damage. Assess the water level and if it is safe to do so, push your car to a higher location. You’ll then want to contact your insurance company and have the car towed to a trusted mechanic for a thorough inspection.

Flood damage to a car can vary depending on the water level and how long it was submerged. Potential issues include engine damage, electrical system failure, brake system damage, and corrosion or mold growth within the vehicle.

To prevent future flooding, always be aware of weather conditions and never drive through flooded areas. Keep your car properly maintained and consider installing a waterproof barrier in the engine bay to protect electrical components.

After a flood, the car must be thoroughly cleaned and dried. Remove all water and mud, then use a wet-dry vacuum to extract moisture from hard-to-reach areas. Next, open all doors and use fans to circulate air, speeding up the drying process. Dehumidifiers can also be used to remove moisture from the air.

Always put safety first when dealing with a flooded car. Be aware of electrical hazards and never touch any electrical components if you are standing in water. Wear protective gear, including gloves and a mask, to avoid contact with contaminants that may be present in the floodwater.