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How Often Should You Change Engine Coolant? (Answered)

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Last Updated on: 7th September 2023, 12:40 am

So your mechanic has recommended a coolant change or you’re wondering when to change the coolant?

A mechanic may advise you to change your coolant every 30,000 miles. Some people will tell you that you don’t need to for a long time. The owner’s manual usually advises replacing the coolant after the first 60,000 miles, then every 30,000 miles after that.

In this article, we’ll explain how often to replace your engine coolant and what would happen if you didn’t replace it.

flushing coolant

How Often to Replace the Coolant

The typical period between flushes for silicated coolants is either two years or 30,000 miles and up to five years or 100,000 miles for an extended drain coolant.

It depends greatly on the vehicle in question, for the most accurate answer you should check the owners manual to see the manufacturers recommendation.

The colour of your coolant will inform you of which kind it is. Silicate coolants are often a green liquid, whereas prolonged drain coolants are frequently gold or orange.

How to Check Your Coolant

While it is always preferable to take your car to a mechanic if you suspect a problem or need something checked, you may also do a quick and easy coolant check on your own.

Make sure the vehicle is cold before placing a clean container under the drain valve. You can usually find the drain valve on the bottom of the radiator.

Open this drainage valve to allow a small quantity of coolant to flow into the container and observe the colour.

If the coolant seems to have rust in it, or if it is a brown hue instead of the original green or orange tint, the coolant must be changed promptly.

If you find any blockages in the coolant piping or in the radiator, this is also an indication that the coolant needs to be changed.

You should also check the level of coolant you have.

You can check the coolant level by opening the engine bay, finding the coolant header tank (usually a small plastic see-through tank with a coloured liquid in it), and viewing it.

On the the header tank (usually on the side) you will see a range of min-max, as long as the liquid level is between the min and max you have a sufficient amount of coolant.

If coolant is below or near the minimum line, you should top it up. If it is above the maximum line you should drain some coolant.

You should check your vehicles coolant level and quality every 1-2 months or so.

Below is a video showing you how to flush your cars coolant.

YouTube video

What Happens If You Don’t Flush Coolant

Corrosion, sediment, and other undesirable items may continue to accumulate in your coolant system if you do not flush it often enough.

Most coolant mixtures have a rust inhibitor included, over time this rust inhibitor will begin to degrade and stop working.

When this degradation happens, rust and corrosion may begin to occur inside the engine block, eventually breaking off and possibly blocking coolant channels and piping.

Over time, sediment may also accumulate, leading to blocked coolant channels too.

A blocked coolant channel or line can cause rapid overheating of an engine, resulting in severe and permanent damage to engine components.

Therefore, just like any service such as changing spark plugs or oil filters, it is essential to replace your car’s engine coolant.

  • 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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