How to Check the Coolant Level and Add It Like a Pro

Every responsible car owner needs to think about keeping their car efficient and in perfect condition. Coolant is an important part of keeping your car safe and in optimal condition. Furthermore, this is the reason why coolant is crucial in preventing the liquids in your engine from freezing and causing your car to break down.

Besides preventing the liquids in your engine from freezing, a quality coolant can help increase your car’s overall performance, keep your engine from overheating and protect it from corrosion. Checking the coolant level and adding more of it when needed isn’t nearly as complicated as you may think. What’s more, it’s well worth your time as it has lots of benefits.

Checking the coolant level and adding coolant to a car.

Why You Need a Coolant

Cooling systems may not have changed a lot over time, but they have become more efficient and dependable. When the coolant level is where it needs to be, it will allow the engine to have the best running temperature and achieve the greatest level of performance.

Your cooling system consists of a liquid coolant that circulates through the engine and cylinder head, and then gets pushed out to the radiator to be cooled. While the coolant is flowing through these passages, heat transfers from the engine components to the tank. This coolant then goes through a rubber hose to the radiator and the air flow entering the engine compartment cools it down. Once this fluid reaches a lower temperature, it goes back into the engine to absorb even more heat.

There is a thermostat between the engine and the radiator to ensure that the coolant stays above a certain temperature so the engine can, in turn, run at the optimal condition. This process is important, because when there’s a high differential in temperatures between the engine coolant and outside air — the heat transfer will be more efficient.

Water is not an efficient heat transfer fluid, and coolant is the only thing that can overcome its shortcomings. Moreover, it’s important to check the coolant level and quality in order to prevent electrolysis and the liquids from freezing or boiling.

When Should You Check the Coolant Level?

As I mentioned, coolant keeps you safe and allows your engine to function properly for a longer period of time. You should check the coolant level for every seasonal change, as different temperatures can affect the fluids in your car in various ways.

For example, coolant is quite useful in low temperatures as they may cause the liquids in your car to freeze. In contrast, high temperatures and warm climates may cause the fluids in your car to evaporate. Needless to say, that can be extremely dangerous for you and can cause great damage to your car.

Furthermore, it’s important to check the coolant level more frequently if you drive your car for longer periods of time or live in a place with extreme weather conditions.

Additionally, you can check the coolant level without opening the cap on the radiator, by looking at the “Full” line on the side of the reservoir. If the liquid level is up to the “Full” line, you’re okay; however, if it isn’t, you will need to add more coolant. Furthermore, if you’re using a non-premixed coolant you will need to add water until it’s at a 50:50 ratio. However, when you buy a premixed one you can just add it as is.

How to Check the Coolant Level

When the coolant is working properly, it will be yellow, red, green or blue in color. However, if it’s rusty, colorless or has something floating in it — flush it straight away. Furthermore, if the coolant is sludgy or too oily, you need to take your car to the mechanic immediately. It’s important to take immediate action as these can be signs of leakage. Additionally, you should only add water to the coolant system in case of an emergency.

1. Park Your Car on a Flat Surface

In order to get an accurate reading of the coolant level, it’s important to park your car on a flat surface and turn it off. The coolant level should be measured when the engine has had the time to cool off and is neither too cold nor too hot.

If you’re going to check the levels after a long drive, make sure you let your car rest for a couple of hours at least. Most importantly, never, under any circumstances, try to check the coolant level while the car is still running.

2. Find the Radiator Cap and Remove It

These caps are pressurized and sit close to the top of the radiator, and are usually labeled on newer cars. However, if yours doesn’t have a label, you can check your owner’s manual to find out where it is.

Once you have found the cap, wrap a rag around it so you don’t burn yourself and then remove it. Alternatively, you can place two fingers and apply pressure to the cap, while simultaneously turning it off with your other hand. In any case, removing the cap carefully will prevent the coolant from bursting out.

3. Check the Coolant Level

In a functioning engine, the coolant level should be at the top of the radiator. Moreover, you should see an etched in “Full” marking where the coolant should reach. In addition to a radiator container, there is an “Overflow” tank where the fluid goes when it gets too hot. There should be little to no fluid here when you check. If there’s almost no coolant in the radiator but the overflow tank is almost completely full, you need to take your car to a workshop immediately.

4. Check the Coolant Protection Level

From time to time, you should check the boiling and freezing points of the coolant. Because your radiator’s ability to absorb heat can decline over time, it’s important to make sure these are working correctly.

You can easily check the coolant protection level in 5 simple steps:

  • Squeeze the hydrometer bulb, to force all the air out.
  • Put the device in the coolant.
  • Release the pressure off the bulb so it can draw in the coolant.
  • Pull the hydrometer out
  • Check the freezing or boiling levels.

If you have a hydrometer with a needle, it will point to a specific temperature range. However, if your device consists of floating balls, they will indicate how well the engine is protected. If these tools show an insufficient level of the coolant, you should add more or flush everything out.

Additionally, you need to examine the protection level every year during spring and fall. However, you should check it more frequently if you are operating your car for longer periods of time or in extreme conditions. Also, always make sure to check the owner’s manual to find the right engine coolant for your car, as different engine types may require different coolants.

How to Add Coolant

First of all, you should never add coolant to a hot, running engine as it can burn you. You also need to make sure to add the exact amount of coolant that your car needs. Additionally, you should add coolant to your overflow tank, or in the reservoir in the radiator, and use a funnel to prevent it from spilling.

1. Turn off the Engine and Make Sure It’s Cool

As I mentioned, adding coolant to a hot engine is not a good idea — in fact, it’s a very dangerous one. Make sure the engine is at a cool or lukewarm temperature before adding the coolant.

2. Open the Hood and Locate the Engine Coolant Tank

Your tank will have a fill range marked on the side. Once the engine is cold, the coolant level should reach up to the “cold fill” mark.

3. Loosen the Reservoir Cap

Take a towel or thick cloth on the reservoir cap before loosening and removing it, because the cap is under pressure. Loosen the cap just a little, and that wait for the pressure to be released. Once that happens, you can remove the cap completely.

4. Add Coolant

Add the appropriate amount of the coolant and make sure you’re pouring it in the correct reservoir. Do not pour it into the radiator. If you’re using a diluted coolant, there’s no need to add anything; but, if you’re using the concentrated one, it needs to be mixed with water at a 1:1 ratio. When the coolant reaches the “cold fill” line, you put the cap back on and twist it until you feel a click.

I found a helpful video if you need help with how to check and test your coolant.

Warning Signs of a Low Coolant Level

You need the coolant in order to drive safely and avoid the sudden breakdown of your engine. You should know how to recognize the problems happening under the hood of your car and what to look for. Be wary if your car is sending you these signals:

Temperature Gauge Too Low or Too High

When the temperature system in your car is at an optimal level, the needle will point to the “Normal” range on the temperature gauge. When the needle starts moving up and down abruptly, it’s a sign of an error in the coolant system.

Most of the time, something that’s blocking the coolant radiator is to blame for this abnormal behavior. This is one of the easiest ways to find out if the coolant in your car is running low and you should add more of it.

Unresponsive Heater

Every glitch in the coolant system can result in consequences to the heater and may result in your engine breaking down. Furthermore, the heater will not be responsible if there is any leakage or blockage happening with the coolant.

Leakage in the Coolant

The coolant can leak both inside and outside of the engine. Moreover, if there are any green, orange or pink fluid marks on the ground, it’s an indication of antifreeze leakage. This could be extremely dangerous and you need to take your car to the nearest workshop. Furthermore, this fluid is highly toxic, make sure to clean it off so children and animals aren’t at risk.

A Mild Smell

Antifreeze has a sweet scent, and if you notice your car suddenly smells differently, you should be concerned. You should also inspect the steam under the hood or the film inside your windshield. Mainly, these are the most common areas where the coolant can leak.

Coolant Light Indicator

The engine temperature is commonly indicated by a thermometer on the dashboard. If the temperature of the engine is higher than usual, the light will start to flicker more often. It may be just a system error, but you should consult an expert nevertheless.

You may also like: Best Coolant Fluids on the Market

Final Thoughts

The consequence of poor coolant upkeep can be catastrophic and even irreversible. Proper and constant car maintenance is the best way to ensure your safety and the health of your car. The cooling system plays a vital role in your engine’s wellbeing. Because of this, it’s important to check the coolant level regularly, so you can add it when necessary.

Additionally, a low coolant level can cause your engine to overheat, develop cracks, and put stress on the water pump. However, the frequency of checks depends on the type of car and its overall condition and driving history.

Coolant circulates through your engine as blood circulates through your veins. Because of this, it’s extremely important to maintain your engine’s proper flow and working temperature. Additionally, coolant is the most important fluid under the bonnet, as it maintains the temperature of your engine. If you’re still not sure how and when you need to check the coolant level, make sure to look at your owner’s guide or consult a mechanic.

Performing regular and correct coolant maintenance includes being diligent, following the instructions from your owner’s guide to the letter, and having a firm understanding of the benefits of using coolant correctly. Furthermore, it’s your responsibility as the owner of a car to understand and correctly select the coolant you’re going to use. Additionally, you should make sure to follow the manufacturers’ instructions on how to check the coolant level and know when it’s necessary to drain the coolant system.




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