Top 3 Best Homemade Radiator Flush (Here’s How to Do It)

When it comes to car maintenance, there are a lot of things that can be done yourself to save money. One such task is flushing your car’s radiator using the best homemade radiator flush method. You can use three different methods, each using common ingredients that you may already have in your home.

This article will teach you the best homemade radiator flush using pure distilled water, vinegar, or baking soda and how to flush your radiator at home!

Here are the Top 3 Best Homemade Radiator Flush Methods

There are three popular methods to flush a radiator at home, and we’ll explain all of the three best homemade radiator flush methods and how you perform them.

Distilled Water

Performing a homemade radiator flush with pure distilled water is a safe way to clean the radiator without damaging it with any chemicals.

Here’s how to flush your radiator with distilled water:

  1. Locate the Radiator. The radiator is located at the front of the car, under the hood.
  2. Remove the Radiator Cap. Screw the radiator cap off by turning it counter-clockwise. Make sure the engine and radiator are completely cool before removing the radiator cap to avoid severe burns.
  3. Drain the Radiator. The radiator’s drain plug is located under the radiator. Place a bucket or a drain pan under the plug and open it to release all coolant inside the radiator. To access the radiator drain plug, you need to jack up your car.
  4. Fill the radiator with distilled water. When the radiator is empty, screw the drain plug on and top off the radiator with distilled water – screw on the radiator cap.
  5. Run the engine for 10 – 15 minutes. Let the engine run for 10 to 15 minutes in order for the fresh distilled water to clear out any debris and contamination inside the cooling system.
  6. Repeat steps 2 – 6 until the water is clear.
  7. Top off the radiator with a mix of distilled water and antifreeze. When your radiator is flushed, top off the radiator with whichever coolant your car needs and enjoy your clean radiator.

50% Vinegar Mixed With 50% Distilled Water

The second method is to flush the radiator with vinegar and distilled water.

Just mix one part of pure white vinegar with one part of distilled water in a bucket or container and pour it into the radiator. Let it soak, empty the solution, and refill the radiator with distilled water.

Here’s how to flush your radiator with vinegar:

  1. Locate the radiator. Under the hood, there’s a cap on top of the radiator at the front of your car.
  2. Remove the radiator cap. Let the engine cool down and unscrew the radiator cap.
  3. Plug the upper and lower radiator hose. Disconnect the hoses and plug them up to avoid vinegar getting inside the engine’s cooling system.
  4. Drain the radiator. Place a bucket or a drain pan under the radiator, and unscrew the drain plug located on the bottom of the radiator.
  5. Fill the radiator with 50% vinegar and 50% distilled water. Top off the radiator with 50% white vinegar and 50% distilled water.
  6. Let it soak for 24 – 48 hours. Let the solution soak the radiator for 1 – 2 days.
  7. Repeat steps 2 – 6 until the water is clear.
  8. Rinse the radiator with pure distilled water. Ensure all vinegar is removed from the system and the water is clear.
  9. Reconnect the hoses and top off the radiator with coolant.

6 Tablespoons of Baking Soda and Distilled Water

Baking soda and distilled water are one of the best homemade radiator flush methods, and it’s becoming more popular every day.

Here’s how to flush your radiator with baking soda:

  1. Locate the radiator. Find the radiator cap in the front of the car under the hood.
  2. Remove the radiator cap. Remove the radiator cap, but make sure the engine is cool before you open it, as a hot coolant can cause severe burns.
  3. Drain the radiator. On the bottom of the radiator, there’s a drain plug you have to open to empty the radiator. Don’t forget about the drain pan or bucked to place underneath.
  4. Remove or turn off the thermostat valve. The thermostat has to be turned off or removed to avoid it getting stuck due to undissolved baking soda.
  5. Fill the radiator halfway with distilled water and 6 tbsp of baking soda, and top it off with distilled water.
  6. Run the engine for 10 – 15 minutes. Let the car run on idle until it’s hot to circulate the cleaning mixture throughout the car’s cooling system.
  7. Repeat steps 2 – 6 until the water is clear.
  8. Flush with pure distilled water. On the last flush, use only distilled water to extract all of the baking soda solution out of the engine’s system.
  9. Top off the radiator with coolant. Reinstall the thermostat valve and refill the radiator with coolant.

Symptoms of a Bad Radiator

Symptoms of a bad radiator can be anything from insufficient heating to coolant leaks.

A radiator works by transferring heat away from the engine. The radiator helps the heat-producing engine to stay at an optimal temperature.

This is important for the car to run properly.

If the radiator is not working correctly, the engine can overheat, causing serious damage and expensive repairs to the engine.

1. Overheating

When driving, you should pay attention to the car’s temperature. If the car’s coolant temperature gets too high, it may mean that something is wrong with your car.

The temperature should be 195-220 degrees Fahrenheit, or 90-105 degrees Celsius, but if it gets too high, something might be wrong, and you need to stop because the engine could get damaged.

One common issue with the cooling system is a bad radiator. A radiator is a metal box that sits in the front of your car that dissipates heat from the engine.

The radiator has tubes running to and from the engine, and coolant flows through the tubes to remove the heat from the hot engine.

Over time, corrosion can build up on the inside of the car’s cooling system, which reduces the effectiveness of the radiator.

If the tubes get too clogged, the coolant can’t flow through them, and the engine will overheat.

As the car overheats, white smoke usually appears from under the car’s hood.

Related: Car Overheating Then Going Back to Normal

2. Leakage

A common sign of a coolant leak is a continuous green or yellow fluid on the ground near your car.

If you see this, it’s important to take your car in for a repair as soon as possible, as not doing so could result in damage to other parts of the vehicle.

Other signs include:

  • An engine that runs hot.
  • A dashboard light indicating low coolant levels.
  • Bubbles in the coolant reservoir.

If you notice your car is leaking coolant, it’s best to take your car to a mechanic to get it checked out.

Read More: Coolant in Oil – Symptoms, Causes & What To Do

3. Dirty or Contaminated

If you see discoloration of the coolant inside the expansion tank or rust inside of the radiator, your cooling system is dirty and contaminated.

Take a few minutes to flush the radiator as soon as possible to avoid any damage to the car due to a dirty or contaminated radiator and cooling system.


Can You Flush an Engine with Vinegar?

You can flush an engine with vinegar as long as you plug the radiator hoses connected to the engine. Mix 50% vinegar with 50% distilled water and let the radiator soak for 24-28 hours.

Can I Flush Radiator with Baking Soda?

It is safe to flush the radiator with baking soda. Make sure you remove the thermostat before you do to avoid the thermostat jamming due to baking soda residue.

Is a Radiator Flush Really Necessary?

The radiator is a vital component of the cooling system in your car. It’s responsible for cooling the engine and preventing it from overheating. The radiator needs to be flushed every two years or 30,000 miles to remove any sediment or corrosion that has built up inside it. If the radiator isn’t flushed, it can cause the engine to overheat and potentially fail.

What Happens If I Don’t Flush My Radiator?

If you don’t flush your radiator, the dirt and sediment built up over time will remain in the system. This can cause the radiator not to function as well as it should and can even lead to an engine failure.

Will a Radiator Flush Help Overheating?

A radiator flush may help with overheating, but it is not a guaranteed solution. If your radiator is severely clogged, a flush may not be able to remove all of the blockages. You may need to have your radiator professionally cleaned or replaced in some cases.


A radiator is an important part of the car that helps to keep the engine cool.

If it’s not working correctly, the engine can overheat and cause serious damage.

There are a handful of symptoms of a bad radiator, including overheating, leakage, and a dirty or contaminated cooling system.

It’s important to flush the radiator or take your car in for a repair if you notice any of these symptoms.

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Robin Söder

Robin has always been passionate about cars ever since young age. Over the years, Robin has worked on thousands of cars and gained invaluable experience in the process. He is considered an expert in his field and is often consulted by other mechanics for advice.

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