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Can You Flush a Radiator With Vinegar (Explained)

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The radiator and the cooling system play a vital role in making sure that the engine works properly. As time goes by, all sorts of grime and junk can build up inside the radiator.

When this happens, the radiator gets blocked and can’t do its job as well. One easy and handy way to get rid of this gunk and make the cooling system work better is by giving the radiator a good clean.

Many people like to use a vinegar (which is basically acetic acid) mix for this flush. However, a pre-mixed coolant system cleaner may be a better option.

Using vinegar to clean a car radiator can be pretty good at taking out rust and other debris from the cooling system. However, vinegar is acidic and might not be the best choice because it can damage some parts.

In this article, we’ll take a closer look at the good and not-so-good reasons for using vinegar to flush a radiator, the steps to do it, and also other ways you can keep your cars cooling system clean.

Signs a Car Radiator Needs Flushing

There are a few tell-tale signs that show your car radiator needs a good cleaning. Below are some of the most usual ones.

  • Overheating
  • Low coolant pressure
  • Steam from engine bay
  • Rust and debris in coolant
  • Weird smells or sounds


If the engine starts to overheat and the coolant temperature increases, it might mean that the radiator is blocked and can’t cool things down properly.

Not Enough Coolant Pressure

When the coolant isn’t pressurized right, it might mean the radiator is blocked and debris has gotten stuck and can’t move the coolant around like it should.

Steam Coming Out

If it looks like your engine is letting out steam, it’s probably because the radiator is stuffed and can’t get rid of heat the right way.

Seeing Rust or Gunk in the Coolant

If you notice rust or any stuff in the coolant, that’s a sign that the radiator is jam-packed and needs cleaning.

Weird Smells or Sounds

Catching a whiff of something odd or hearing strange sounds from where the engine is? That might mean your cooling system and radiator has an issue.

These signs might be caused another issue, so it’s a good call to have someone who knows their stuff take a look to figure out if cleaning the radiator is what’s needed.

Giving your car regular check-ups, and including cleaning the radiator in them, is a smart way to stop these problems from showing up to begin with.

rust in coolant

Is Vinegar a Good Radiator Flush?

You can use vinegar to clean your radiator, but it’s not the top pick for the job. The issue with vinegar is that it’s super acidic, having a pH close to 2.5.

What this means is that vinegar can eat away at components, and this can harm the radiator’s metal and other parts of the cooling system, like anything made of rubber.

Using straight-up vinegar can even eat into metals like stainless steel, and this can cause leakages and other headaches.

A smarter choice is to use baking soda or a cleaner that’s specially made for cooling systems.

How Much Vinegar to Use

If you’re set on using white vinegar to give your car’s cooling system a bath, it’s key to get the amount right. Different cars will need different amounts of cleaning mix.

A good rule of thumb is to use a mix of two parts water to one part vinegar. This helps water down the vinegar’s acidity and reduces the risks of harming the radiator or cooling system.

So, for instance, if you’re using 2 litres of water, you should mix in 1 liter of white vinegar.

Be sure not to let the vinegar sit in the radiator for too long (no more than 10 minutes) to avoid any chance of it eating away at anything.

infographic showing to use a 2:1 ratio of water to vinegar when flushing a cars cooling system

Can White Vinegar Clean the Cooling System?

White vinegar holds a prominent place among various vinegar types utilized for cleaning radiators due to its affordability and easy accessibility.

However, it’s vital to be cognizant of its highly acidic nature and exercise prudence while using it.

There exist more effective approaches and substances for cleansing a car radiator, such as using baking soda or a specially formulated solution.

Is Vinegar and White Vinegar the Same?

No, there’s a distinction between vinegar and white vinegar.

Vinegar is an umbrella term encompassing multiple kinds of vinegar, whereas white vinegar is the specific variant suitable for purging a cooling system.

Vinegar is a broad designation for an acidic fluid produced via the fermentation of carbohydrates. It manifests in an array of variants, including apple cider, balsamic, red wine, among others.

Every vinegar variant possesses its distinctive taste and scent, and varies in acidity levels, which usually range from 4% to approximately 7%.

White vinegar, alternatively referred to as distilled vinegar or spirit vinegar, is exclusively produced by distilling diluted ethanol.

This process yields a transparent and colorless liquid, notable for its potent aroma. White vinegar has a considerably high acidity, typically hovering around 10%.

Is White Vinegar Detrimental to Metal?

White vinegar has a corrosive effect on metal and can inflict harm if deployed in concentrated form. Hence, it’s imperative to water down the vinegar before employing it for radiator flushing.

Can You Flush a Heater Core with Vinegar?

Flushing a heater core with vinegar is ill-advised since the heater core is composed of aluminum, which can corrode and get damaged by vinegar.

Nonetheless, when you flush the entire cooling system, the heater matrix is likely to be purged in conjunction with coolant or another solution.


Executing a radiator flush is a critical component of sustaining a car’s cooling system. Although white vinegar is an option for this purpose, its elevated acidity makes it a suboptimal choice.

It is more advisable to opt for a cooling system cleanser that is pre-mixed or to use baking soda.

If you elect to utilize vinegar, it’s essential to mix it with water and administer the appropriate quantity. Employing an incorrect blend or an excessive amount of vinegar can wreak havoc on the radiator and the cooling system.

Don’t forget to take into account the materials comprising the cooling system and the pH levels of the solution prior to executing the flush.

  • 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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