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How to Clean a Radiator With Baking Soda (Step-by-Step)

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  • 9 min read

Last Updated on: 7th September 2023, 12:47 am

The radiator is a key part of a vehicle’s cooling mechanism. Its role is to ward off engine overheating, which it achieves by distributing heat through a coolant and a series of fins.

Over time, the radiator may gather rust, debris, and other pollutants that can reduce its performance and potentially lead to expensive repairs. One way to maintain it is by cleaning and flushing it with a baking soda mixture.

This article will walk you through a detailed process of how to use baking soda to clean and flush a radiator.

Additionally, we’ll tackle some frequently asked questions about this particular method of maintaining a cooling system.

What Does a Car Radiator Do?

The primary role of a car radiator is to disperse heat away from the engine, helping to prevent it from reaching excessive temperatures.

Typically positioned at the front of the vehicle, the radiator is linked to the engine through a series of hoses.

When the engine operates, it produces heat that is then taken up by the coolant circulating within the engine.

Heated coolant subsequently travels into the radiator, where it gets cooled as it moves through a complex grid of fins.

This vital process ensures that the engine maintains an optimal running temperature.

car radiator

Signs of a Clogged Radiator

Below are some usual indicators of a blocked radiator that might require a flush.

However, it’s crucial to remember that these symptoms could also arise from other problems, like a faulty thermostat or water pump.

Therefore, it’s always recommended to seek the expertise of a professional mechanic for accurate diagnosis and repair.

  1. Engine overheating
  2. Low or high coolant pressure
  3. Steam coming from the engine bay
  4. Rust or debris in the coolant
  5. Unusual smells of noises

1) Engine Overheating

A blocked radiator hinders effective heat dissipation, resulting in the engine operating at temperatures above the normal range.

This can be signaled by a temperature gauge showing an unusually high reading or a coolant temperature warning light flashing on the dashboard.

In more severe situations, the engine might even power down to prevent damage from overheating.

coolant temperature gauge on a car dashboard

2) Abnormal Coolant Pressure

Blockage in a radiator can lead to unusually low or high coolant pressure, potentially resulting in leaks and additional engine damage.

The pressure of the coolant plays a vital role in its circulation through the engine and the radiator. If this pressure drops, it could disrupt the proper flow of the coolant.

You may detect this issue if you see a low coolant light on your dashboard or notice visible leaks of the coolant.

3) Steam From the Engine Bay

When you see steam emerging from the engine area, it’s a clear sign that the radiator isn’t efficiently dispelling heat.

This issue could be caused by a blocked radiator, resulting in the coolant getting too hot and turning into steam.

4) Rust in the Coolant

If you notice rust or foreign particles in the coolant, it indicates that the radiator is blocked and needs cleaning.

The rust and foreign particles might originate from various sources, like corrosion or rust in the radiator or hoses, or debris entering the cooling system.

rust in the coolant

5. Unusual Smells or Noises

Should you notice any strange odors or sounds emanating from the engine, it might indicate a blocked radiator.

The peculiar smells could be the result of overheated coolant, which can produce a sweet or burnt aroma, or they could stem from rust and foreign particles present in the coolant.

The unusual noises might be caused by improper coolant flow, leading to noises such as knocking or ticking.

How to Flush a Radiator With Baking Soda

Using baking soda to clean your car’s radiator is an easy and effective technique for getting rid of clogging debris and accumulation, which can impact the radiator’s performance.

Below is a step by step a guide to help you flush your car radiator with baking soda.

  1. Let the car cool down
  2. Get equipment ready
  3. Determine vehicles coolant capacity
  4. Prepare the baking soda mixture
  5. Remove the radiator cap
  6. Dispose of old coolant fluid
  7. Pour in the baking soda mix
  8. Let the mixture sit
  9. Run the engine
  10. Drain the baking soda mixture
  11. Rinse the coolant system with distilled water
  12. Refill with normal coolant fluid
  13. Seal the radiator and test
  14. Monitor the coolant level

1) Let your car cool down

It’s crucial to wait for your car to fully cool down before initiating the cleaning process, as the radiator and engine get very hot, and dealing with them while hot can lead to burns or injuries.

2) Get your equipment and materials ready

Make sure to have all necessary items for the job, including the following.

3) Determine your vehicle’s coolant capacity

Each vehicle requires a different amount of coolant. Therefore, knowing your vehicle’s specific coolant need is key before you start cleaning the radiator.

You can find this information in the car’s owner manual or get it from a professional mechanic.

4) Prepare the baking soda mixture

Pour 5 teaspoons of baking soda into every 1 litre of water in a bucket. Stir until the baking soda completely dissolves.

5) Remove the radiator cap

You’ll need to carefully take off the radiator cap to reach the coolant and enable an easier drainage of the coolant.

6) Dispose of the old coolant

Find the drain valve at the bottom of the radiator, open it and let the old coolant flow out into a bucket or container for proper disposal. Once you’re done draining, close the valve.

7) Pour in the baking soda mix

Using a funnel, pour your baking soda solution into the radiator.

8) Let the mixture sit

Let the baking soda solution stay in the radiator for about 5-10 minutes to dissolve any debris or accumulation.

9) Run the engine

Switch on the engine and let it operate for 10-15 minutes. This allows the baking soda mix to circulate through the entire cooling system.

10) Drain the baking soda mixture

Open the drain valve to let the baking soda solution flow out of the radiator. Make sure you have a bucket or container ready to collect it for appropriate disposal.

11) Rinse the cooling system with distilled water

Rinse your radiator with distilled water to remove any leftover baking soda mix and debris. Repeat this process until the water that comes out is clear.

12) Refill with the usual coolant

After ensuring that your radiator is clean and the exiting water is clear, pour the required amount of the usual coolant into the cooling system.

13) Seal the radiator and test the car

Put the radiator cap back on and take your car for a spin to ensure the cooling system is functioning properly.

14) Monitor the coolant level and top off if necessary

Post the test drive, keep an eye on the coolant level and refill as necessary.

Remember, safety is paramount when executing this process. Use rubber gloves and safety goggles.

If you’re unsure at any stage, it’s best to contact a professional mechanic for accurate diagnosis and repair.

Can You Put Vinegar and Baking Soda in a Radiator?

It’s generally not advisable to use vinegar and baking soda simultaneously in a radiator, though you can use baking soda before or after flushing the radiator with vinegar.

A chemical reaction happens when vinegar meets baking soda, resulting in the release of carbon dioxide gas and the formation of a liquid mixture, which is predominantly water and a salt known as sodium acetate.

However, this liquid shouldn’t be poured into a radiator because it could potentially harm the metal and lead to leaks.

What Occurs When Vinegar and Baking Soda Combine?

The reaction that takes place when vinegar, an acid, comes into contact with baking soda, a base, results in the following.

  • carbon dioxide gas
  • water
  • sodium acetate, a type of salt

This is recognized as an acid-base reaction, which causes a fizzing and bubbling effect.

For the best results and to prevent any complications, it’s recommended to use vinegar and baking soda separately when flushing the cooling system.

Is Baking Soda and Bicarbonate of Soda the Same?

Yes, they are. The terms baking soda, sodium bicarbonate, and bicarbonate of soda all refer to the same substance and can be used interchangeably.

Is it Safe to Clean a Radiator Using Baking Soda?

Yes, it’s generally safe to cleanse a radiator with baking soda, provided that necessary safety measures are in place.

This includes wearing protective gear like rubber gloves and safety goggles, and following the correct radiator flushing procedure.

Nevertheless, be aware that prolonged exposure of baking soda can lead to damage to the metal components and cooling system.

So, it’s crucial to stick to the suggested duration for the baking soda solution to sit in the radiator.

Can I Do a Car Radiator Flush on My Own?

Absolutely, you can perform a car radiator flush on your own if you possess the right tools and knowledge.

However, if you’re uncertain about the procedure or if your car has particular features, it would be wise to seek advice from a professional mechanic.


A blocked radiator can result in reduced performance and expensive fixes. A practical method to clean a radiator involves the use of baking soda.

The process of using baking soda to flush a radiator includes creating a solution by mixing it with water, pouring this mixture into the cooling system, running the vehicle’s engine, and finally, draining the cooling system.

After draining, it should be flushed once more using distilled water.

Adhering to the right procedures and wearing protective equipment is essential when flushing a radiator. If there’s any uncertainty, it’s advised to reach out to a professional.

Utilizing baking soda is a secure and effective technique for enhancing the performance of your radiator by cleaning it.

  • Andy Lewin

    Andy Lewin is a senior mechanic, ASE qualified master technician, and an experienced automotive engineer. He's passionate about serving the automotive community with the highest-quality and trustworthy information on all things automotive. He loves to write about car repairs, maintenance, car modifications and tuning, faults, and much more.

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