How to change coolant in car

Curious about how to change your car's coolant? You’ve come to the right place. At BrokerLink, we’re all about keeping you informed—whether it’s about car maintenance or car insurance. Stick around to learn how to change your car's coolant and how the right auto insurance can keep you covered on the road.

What is car coolant?

Car coolant is a special liquid, usually made from propylene glycol, that helps keep your engine from overheating while also lubricating its moving parts. As you drive, your engine can reach scorching temperatures—up to 4,500°F—hot enough to melt things you definitely don’t want melting. That’s where coolant comes in, circulating through the engine to maintain the perfect temperature.

While pure water might cool your engine even better, it comes with a big downside: rust. Coolant, on the other hand, not only keeps things cool but also protects your engine from corrosion, helping it run smoother and last longer.

How to check your coolant level

Before you check your coolant level, here’s the most important thing to know: never do it while the engine is hot. After driving, your engine, car radiator, and reservoir can get extremely hot, and you don’t want to touch the reservoir cap or radiator hoses until they’ve completely cooled down. When the system is hot, it’s also under high pressure, and opening the cap could cause hot coolant to spray out, which can lead to serious burns. Play it safe—always wait until everything is cool before checking your coolant level. Here’s how to check your coolant level:

1. Locate the coolant reservoir

When you pop the hood, the first step is to locate the coolant reservoir. The car's radiator cap is usually labelled "coolant," so it should be easy to spot. If you’re having trouble finding it, check your owner’s manual—it’ll not only show you where it is but also tell you the correct type of coolant for your vehicle to prevent freezing and corrosion.

2. Look for where the cool level is

The reservoir is translucent and has "L" (low) and "F" (full) markings on the side, so you can see the coolant level without opening the cap. If the fluid is close to or below the "L," you’ll need to add more coolant.

If your engine coolant warning light comes on, it usually means the coolant level is low, or there’s a problem causing your engine to overheat. If you’re unsure about the refill process, or if you think it's something else that's causing your engine to overheat, it’s a good idea to take your car to a mechanic to have it checked out.

Steps for changing your car's coolant

Now that you know how to check your coolant levels, let's move on to how to change the coolant. Here's our step-by-step guide to help you out:

1. Check your owner's manual

The amount and type of coolant your car needs can vary a lot depending on the engine, so it’s important to check this ahead of time. Some cars only need four or five quarts, while others might take up to fourteen. You can find the exact details in your owner's manual, so it’s worth taking a quick look at it before you start. This way, you'll know how much you need to buy before you begin.

2. Wait for the car to cool down

Park your car on a flat, dry surface, set up some wheel chocks for extra safety, and give the engine plenty of time to cool down before you get started.

Most cars run at over 200 degrees Fahrenheit, and all that heat can really build up under the hood. Your radiator helps manage this by circulating coolant through the engine and then into the radiator, where it’s cooled by airflow and the fan. But that process makes the fluid inside your radiator extremely hot—and under pressure. If you open the cap while it’s still hot, you risk releasing steam or coolant that could burn you. To stay safe, give your car a few hours to cool down if it’s been running recently. Better safe than sorry!

3. Look for any signs of damage

Start by popping the hood and securing it in place. Take a good look at the radiator and its hoses, checking for any cracks, leaks, or signs of wear. If you’re planning to do a full system flush or just a radiator drain, this is the time to inspect everything closely.

Pay special attention to the hoses—look for any leaks, cracks, or areas where the rubber seems worn or stressed. If you notice damage, you’ll probably need to replace the hose. If you’re a complete flush of the cooling system, this is also the point where you’d install a flush kit into the heater hose.

4. Remove the radiator cap

When the engine and radiator are completely cool—ideally after the car has been off for at least an hour or more—carefully press down on the radiator cap and remove it. And we know we keep saying it, but never try this when the radiator is hot; it can be extremely dangerous.

5. Locate the drain valve and open it

Your radiator sits at the front of the engine bay, right behind the car’s grille. You’ll likely see one or two fans mounted on its front-facing side, with plastic or metal end tanks on either side of the aluminum body. To drain the radiator, look for the drain valve, usually located near the bottom of the driver’s side end tank.

Depending on your car’s make and model, the valve might have a plug called a “drain cock.” Place a pan under the drain valve to catch the old coolant. Then, open the valve or loosen the plug and let the coolant flow out. Once it’s completely drained, tighten the plug and close the valve back up.

Note: Make sure the coolant doesn’t end up on the ground or in a drain—it’s harmful to the environment and against the law. Always dispose of it properly at a designated recycling or disposal facility.

6. Fill the radiator with distilled water

Start by pouring water into the radiator or coolant reservoir. If you’re using a flush product, follow the specific steps on the bottle—these can vary depending on the brand. Generally, you’ll fill the system with both water and the flush product. Using a flush product is great for breaking up sediment or corrosion and clearing it out of the system.

7. Replace the radiator cap and run the engine

Once it’s filled, close the cap and start the engine. Turn the heat on full blast inside the cabin and let the car run for about 10 minutes. This circulates the water through the coolant system, helping flush out any remaining old coolant. After 10 minutes, turn off the engine and let the car cool back down. After it's completely cooled, repeat step five to drain the water/flush product out.

8. Loosen the radiator hose and flush

After running the flush through and draining the radiator again, it’s a good idea to clear out any leftover sediment that the drain might have missed. Start by loosening and removing the lower radiator hose. Then, fill the radiator with water and let it drain out through the bottom into the pan. This will help flush out any sediment or remaining coolant that’s settled at the base of the radiator.

At this point, most of the water won’t contain much antifreeze, but you’ll get rid of a lot of the debris. Once that’s done, connect your hose to the flush valve you installed as part of your flush kit earlier and follow the product instructions to finish flushing the system. Then, drain out the last of your dirty flush water into the pan with drained coolant and close the drain valve.

9. Add new coolant to the radiator

Remember when we said to check your owner’s manual to find the right coolant for your car? Now’s the time to put that info to use. Most vehicles need a 50/50 mix of coolant and water, so you can either mix it yourself or grab a pre-mixed coolant bottle option from your local store. Just make sure to add the right amount of coolant and water mixture as specified in your owner’s manual—it’s important to match what your engine needs!

Pour coolant into the same spot where you added the water earlier. In some systems, you’ll need to pour it in slowly so the fluid has time to flow through the reservoir and into the coolant lines. Take your time to avoid any spills or overflows under the hood of your car.

10. Replace the radiator cap and start the engine

Start the engine and let it run for about 10 minutes with the heater turned on high. Keep an eye on the temperature gauge as the water and coolant mixture circulates through the system. It’s normal for the gauge to rise a little before settling back to the normal range, usually marked in blue or near the middle of the gauge.

If the temperature starts climbing toward overheating, turn the car off and double-check the coolant level to ensure it’s properly filled. After running the engine for 10 minutes and seeing a normal temperature reading, you’re all set—the coolant change is complete!

When to check your coolant level

As we mentioned, coolant works by circulating through your engine, absorbing heat and releasing it into the air through the radiator. Over time, some of it can evaporate, causing the level to drop over time. Since coolant is essential for keeping your engine running at the right temperature, it’s a good idea to check your coolant levels regularly. A good rule of thumb is to check it twice a year—check all your car's fluid levels, like your transmission fluid and power steering fluid, aspart of your summer and winter car maintenance checklists.

Contact BrokerLink today

Keeping up with vehicle maintenance is key to keeping your car in great shape. One important part of this is making sure all your fluid levels are topped up—especially coolant. Coolant plays a big role in keeping your car running smoothly, and the better your car handles, the more control you have on the road. That means you’re less likely to end up in an accident, which can help you avoid filing car insurance claims and keep your rates lower.

Of course, accidents can still happen, and that’s where car insurance comes in. If an accident damages your car or even your radiator, your coverage might help with the repair costs. A few types of auto insurance that could be helpful in these situations include:

• Liability car insurance
• Accident forgiveness coverage
• Comprehensive car coverage
• Collision car coverage
• Accident benefits coverage

To find out how much car insurance costs where you live, contact BrokerLink for a free insurance quote. You can reach us by phone, email, or in person at any one of our locations throughout Canada. No matter how you choose to get in touch, a BrokerLink insurance advisor will be happy to assist you. We also encourage you to take advantage of our free online quote tool that can provide you with a competitive quote in minutes.

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