How To Flush Your Radiator With Vinegar or Baking Soda (Is It Safe?)

Flushing the radiator with vinegar or baking soda is an interesting idea that is surprisingly effective when done right. With proper maintenance, the radiator can operate for hundreds of thousands of miles without showing any warning signs. However, once the engine temperature starts to increase, you should take the necessary steps to prevent overheating.

Signs of a Bad Radiator

The reason why the radiator is placed in the front of the vehicle is to have as much air circulating through it as possible. Air drag forms when the car is moving, causing a resistance that requires extra power to overcome. Vehicle design has changed over the years to reduce the air drag coefficient, but the vents of the grille still purposefully direct air inside the engine bay, and into the radiator.

Without going into too much detail, the engine cooling system consists of a radiator, radiator fan, pipes, and a water pump. A fault in the system results in inefficient cooling and overheating of the engine. The following are the main signs of a bad radiator.

 1. High Temperatures and Overheating

When driving, it’s important to keep an eye on the temperature gauge. The dial starts at the bottom of the gauge, and gradually climbs to the optimal engine operating temperature. Every vehicle is different, but in general, the engine should run at operating temperatures between 195 and 220 degrees.

If the temperature climbs beyond normal levels, or if the engine overheats in a cloud of white smoke, that means there’s something wrong with the cooling system.

 2. Leaking Coolant

Unlike oil, coolant is clear and has a strong chemical smell to it. If you find drops or puddles forming underneath your vehicle when it’s parked, check the viscosity and smell to identify the liquid. If it’s coolant, it indicates a leak in the system.

 3. Dirty Coolant

To identify the quality of coolant, open the coolant expansion tank when the engine is cold and take a look inside. Significant discoloration, forming of sludge, and particle build-up could be caused by serious engine problems. However, the first thing to do is flush the coolant and clean the radiator to remove them as potential causes.

How to Flush Your Radiator With Vinegar

Flushing the radiator with vinegar is a very effective way of cleaning out all the debris and residue that accumulated over the years. Contrary to some guides, I would not recommend flushing the entire system with vinegar. We’ll touch upon that later, as we’ll now go through the steps of flushing the radiator.

  1. Raise the vehicle with a jack, then place jack stands to secure it in place as you’ll have to get underneath the vehicle.
  2. Place an oil pan or a bucket underneath the radiator and open the drain plug located at the lowest point of the radiator.
  3. Disconnect the upper and lower radiator hose.
  4. Plug up the hose connection points to seal the radiator.
  5. You can choose to pour either 50% distilled water and 50% white vinegar mixed up, or pure white vinegar.
  6. Let it soak overnight or longer if you have time. One to two days should be enough.
  7. Release the liquid, then rinse the radiator with distilled water. If it’s still dirty, plug it up, add vinegar and let it soak one more time.
  8. Rinse all the vinegar out of the system. Once the distilled water becomes clear, you can reuse it a few times to make sure the rinse is good. Finish up with a batch of pure water.
  9. Reconnect the hoses and refill the coolant.


Alternatively, you can connect a cheap water pump on step 4. Instead of letting the vinegar soak, you’ll run it through the system with the pump, which is faster but less efficient. The rest of the steps remain the same.

How to Flush Your Radiator With Baking Soda

Flushing with baking soda is another way of cleaning the radiator. The process is easier than using vinegar but provides varying results.

  1. Take off the thermostat valve to prevent clogging with undissolved baking soda.
  2. Flush out the coolant by unplugging the release valve at the bottom of the radiator. Use an oil pan to safely collect the liquid.
  3. Fill up the radiator halfway with distilled water, add 6 tablespoons of baking soda, then continue with water until you’ve reached the specified limit.
  4. Close the radiator cap and turn on the engine. Let it get hot and circulate the water-baking soda mix through the system.
  5. Wait for the engine to cool off, then flush out the water. Repeat the process until it becomes clear. Then do it one last time with pure distilled water.
  6. Flush out the water and refill the radiator with coolant. Make sure to return the thermostat valve in its place.


Is it Safe to Flush Your Radiator With Vinegar?

Vinegar is a mild acid that can corrode metal and deteriorate rubber hoses. Letting it run into the engine block, through the hoses and water pump gives it more opportunities to remain in the system even after flushing. You can get away with flushing the system without taking off the hoses, but it’s best to disconnect the radiator fully.

With that in mind, flushing with vinegar is safe and very effective. If you’re having radiator issues, I would recommend using it over the baking soda.

Is it Safe to Flush Your Radiator With Baking Soda?

Baking soda is a chemical base, making it much safer to run through the system. Adding too much can definitely harm the system, but you should be okay with the recommended amount and proper flushing.

Should I Flush Radiator With Baking Soda and Vinegar Combined?

When you combine an acid with a base, they will cancel each other out. This is one of the fundamental rules of chemistry, yet so many guides claim that combining vinegar, baking soda, and distilled water is a good way of cleaning the radiator. Some state the forming of CO2 is what cleans the radiator, yet I would argue that vinegar can do a better job on its own.

Until I run my own tests, I cannot claim this with certainty, but I would say that flushing the radiator with baking soda, vinegar, and distilled water is no different than using only distilled water. The chemical reaction between vinegar and baking soda forms gas and liquid, so at least there’s no risk of damage to the engine or cooling system.


What is the best thing to use to flush a radiator?

Vinegar is the best-value solution for flushing the radiator, but professional solutions are more effective. Prestone AS105 Radiator Flush and Cleaner is a great product for the job. A solid alternative is Liqui Moly 2051 Radiator Cleaner that reduce running temperatures by up to 15 degrees.


Can you flush a radiator with Dawn dish soap?

Adding dish soap to the coolant is one of the fastest ways to destroy the engine. Not only is it going to chemically affect components, but the bubbling will also reduce cooling effectiveness, cause problems with the water pump and likely build up pressure that will blow the safety gasket.

How can I flush my radiator at home?

The steps explained above are all easily accomplished at home. If you can get below the radiator and unhook the hose without a jack, then all you need is a bucket, a lot of distilled water, and vinegar or baking soda. Radiator coolant is a toxic liquid, so find a way to dispose of it safely.

What happens if you put laundry detergent in your radiator?

Similar to dish soap, using any chemical lying around the house inside the house is a very bad idea. The engine and the radiator are made very durable because the engineers only had to worry about certain chemicals and elements affecting it. By adding a foreign chemical to the mix, there’s no way to tell what will happen, but it’s certainly not going to end well.


As you can see, flushing the radiator with either vinegar or baking soda is a surprisingly effective way of getting the particles and sludge out of the system. The important thing is to do a good job of clearing out all the traces of either product before filling the radiator up with coolant and driving the vehicle. If this article helped you solve your radiator and overheating problems, then you should check out our other guides and learn more about vehicle maintenance!