How to Stop Rust From Spreading on a Car

Natural elements and artificial forces, including snowfall, sweltering heat, and road salt, can take a toll on your car’s metal, creating the perfect conditions for rust. When rust sets in, your vehicle may degrade and lose value if left unchecked. Fortunately, there are ways to stop rust from spreading on your car.

Eight ways to stop rust from spreading on a car

  1. Repair rust on your car.
  2. Wash and wax your car’s body regularly.
  3. Regularly wash and inspect the undercarriage.
  4. Be wary of scratches.
  5. Keep an eye on your paintwork.
  6. Look for the weak spots.
  7. Check your local area weather patterns.
  8. Park in a garage.
Rust spreading on a car.

1. Repair Rust on Your Car

You can’t completely prevent your car from rusting. However, what you can do is keep it within manageable levels. Your vehicle will still be exposed to the elements somehow, no matter how well you care for it. When you notice rust on your car’s body or undercarriage, the trick is fixing it before it gets worse.

Repairing your car after rusting isn’t particularly tricky, but it can be time-consuming. Choose a calm day to fix rusty spots on your car’s doors and the hood. You’ll need to spend roughly $100 on rust repair supplies, which include:

  • Sandpaper
  • Premier
  • Masking tape
  • touch-up paint
  • Polishing compound
  • Clear coat

Follow these steps to fix rust spots on your car:

Shop for rust repair supplies 

  1. Find your car’s paint code. Your car’s paint code could be on the body, trunk, engine, etc. You can also use online resources like and to determine your car’s paint code.
  2. Next, buy the touch-up paint. It would be best to purchase aerosol cans and roller applicators to repair rusted spots to make application easier. The latest car models have a base/clear coat paint. The base has color pigment and resins, while the latter is only a gloss. You’ll need the same amount of both products to finish the job.
  3. Buy epoxy and lacquer primers. The former eats into the metal, and the latter holds the paint. 
  4. You will need a sanding block, grit sandpaper, wax and grease remover, painter’s tape, microfiber piece of cloth, poly sheet, and a tuck rag.

Use Tape to Mark the rusted spots 

Tape the periphery of the sheet a few feet from the rusted spots to give you more room to integrate the paint with the car’s existing paint. You can use tape to mark off the places where you’ll need to repaint, making it easier to work on specific rusted areas on your car.

Remove the rust

  1. Carefully sand any peeled paint with sandpaper (40 grit should suffice) to expose bare metal.
  2. Use a greater grit sandpaper to enlarge and feather the spot.
  3. Switch to a 220 grit to finish off the feathering.
  4. Dust particles off the sanded area with a tuck rug.
  5. Clean the dusted spot with a detergent
  6. Apply the self-etching epoxy primer, then the filler primer
  7. Sand the primers
  8. Spray the base coat
  9. Spray the clear coat

Removing rust is one thing; ensuring it doesn’t recur is another. Would you want to repair rust on your car every time it happens? Why not prevent or minimize its spread so that you don’t have to fix it now and then? Of course, repairing rust prevents it from spreading, so you’ll need to do this at some point.

You may also like to read: How Fast Does Rust Spread on a Car?

This YouTube video will show you how to repair rust on your car:

2. Wash and Wax Your Car’s Body Regularly

Some areas are prone to rusting more than others. But either way, you should wash your car regularly to keep it looking neat and remove any rust accelerants that may have attached to nooks and crevices.

If you thought washing your car with your regular household soap was sufficient, you likely did more harm than good. Regular soaps and detergents strip your car’s paint of any protective wax, leaving it exposed. They also promote algae growth on the car’s paint.

Regular household soap doesn’t stop rusting. So, using recommended car wash detergents would help. 

You can buy Rain-X 5072084 Foaming Car Wash (available on and use it instead of household soap. It’s safe for all vehicle surfaces, it’s biodegradable, and doesn’t dull waxed vehicle surfaces.

After washing your car, dry off any water droplets on the paint, and open the doors to let water drain off the rocker panels. Next, wax your car and cover it with a car cover to protect it from the elements.

Not only does washing and waxing your car prevent rust from occurring, but it also prevents rust from spreading by removing salts from scratches and exposed surfaces.

3. Regularly Wash and Inspect the Undercarriage

The undercarriage is often forgotten during a car wash, yet it’s the area most vulnerable to rusting. Just peep under your car and tell me what you see – rust. The undercarriage suffers the most from hitting rocks, road salt, and water splashes. All these are ideal conditions for rusting. It’s also made worse because inspecting the underside of your car isn’t always intuitive.

Regularly wash your car’s undercarriage using diluted detergent. Choose an even surface away from gravel to avoid small rock pieces hitting your windscreen and paint.

Mercedes-Benz knows the importance of keeping a car’s undercarriage clean. The automaker has introduced a new undercarriage wash function on its GLS-Class SUV 2020 model. When you activate the carwash mode, the vehicle will raise its body with adjustable suspensions so you can easily access the undercarriage and the wheels.

4. Be Wary of Scratches

Scratches are not entirely avoidable. Sometimes the worst happens, and there’s nothing you can do about it. When your car’s paint gets the slightest of scratches, be quick to repair it to prevent any rust that may have developed from spreading.

Scratches open up your car’s metal to moisture, which accelerates rusting. It can quickly get worse if you live near the seaside or frequently drive through areas with lots of winter road salts.

Here’s how to avoid scratching your car’s body:

  • Avoid parking too close to other vehicles in the parking lot.
  • Avoid carrying heavy luggage on your car’s roof.
  • Don’t park under trees. Bird droppings contain chemicals that can damage the car’s paint and make scratches vulnerable to rusting.
  • Avoid parking your car under water gutters.

5. Keep an Eye on Your Paintwork

Rust develops when iron reacts with oxygen to form iron oxide. Water and salt speed up the process. The paintwork forms a barrier or a protective coat over your car’s body, protecting it from water and moisture in the environment. So, the paint prevents the vehicle from rusting. And rusting would occur if your car’s paint is damaged.

Get your paint touched up if you notice the top gloss coat flaking or spots with paint chipped off. The car’s paint doesn’t only make your car look pretty; it’s a protective layer that you should maintain.

6. Look for the Weak Spots

Some areas of your car are more prone to rusting than others. There are small areas where moisture and rust accelerants will stick and won’t come off quickly. These areas include:

  • The sunroof
  • Wheel wells
  • Cracks and crevices
  • Under the car’s trim
  • The vehicle’s undercarriage
  • Points where the side mirrors connect to the body

Grab a torch and inspect all these spots to check if rust has already set it. Scratch off any rust or dirt, clean, and apply wax appropriately.

7. Check Your Local Area Weather Patterns

Keep tabs on your local weather patterns. Check to see when it’s going to rain or snow next. Remember that high temperatures can ultimately accelerate rusting.

Keeping an eye on weather patterns will help determine when to rehabilitate your car’s paint to avoid further rusting when conditions become suitable. If it’s going to rain in your hometown for the next few days, you’d want to reschedule your daily routes to avoid ones with large water puddles and dirt roads.

If it’s going to snow, you’d want to avoid roads with lots of deicing salt and schedule to get your undercarriage washed.

8. Park Your Car in a Garage

It wouldn’t make sense to park your car in the same conditions that caused it to rust in the first place. You can park under shade if you can’t afford a garage. This will keep your car from moisture, snowfall, bird droppings, and direct sunlight that could potentially damage the paint.

Ensure your shade is in an elevated and well-drained area to avoid water collecting under your car.

Key Takeaways

It’s impossible to keep your car completely free of rust, but it’s possible to keep it looking great with minimal rust. It all comes down to rehabilitating the already rusted parts and keeping it from moisture. 

These tips will do the trick:

  • Repair any rusted portions
  • Clean your car’s body and undercarriage regularly
  • Park your car in a garage or under a shade
  • Maintain your car’s paint
  • Avoid paint scratches as far as possible

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