Informational Guide

How To Check Your Vehicle’s Coolant Level

Coolant is essential for keeping an engine at a proper temperature. Learn how to check the coolant level in a radiator here.

The coolant in your vehicle is essential for keeping the engine at a proper temperature. To ensure everything is running the way it should, you must know how to check the coolant level. Our detailed guide will teach you how to check the coolant level in a radiator and show you the proper way to care for your vehicle.

  • Inorganic Acid Technology (IAT) 
    This is the most conventional coolant on the market. You will know this coolant by its green color. IAT has been used for decades but is slowly being replaced because it breaks down quickly. Cars with this type of coolant will need more regular tune-ups and servicing appointments.
  • Organic Acid Technology (OAT) 
    OAT coolant provides an upgrade to the conventional type. This coolant is usually orange, purple, red, or yellow. The OAT has a longer life thanks to some additives that were included. Because it won't break down as easily, it helps the car go longer between service appointments.
  • Hybrid Organic Acid Technology (HOAT) 
    With the HOAT coolant, you get a hybrid mixture of the IAT and OAT types containing a yellow or orange color. With HOAT coolants, you can count on reliable cooling power, plus a longer lifespan.
coolant level

Warning Signs Of Low Or Empty Coolant (How To Know?)

You want to know how to check engine coolant level if you see any of these warning signs.

  • Dashboard warning light comes on. This light indicates that the coolant level is too low, and your engine might start overheating.
  • Temperature gauge begins rising. Anytime that the temperature of the engine exceeds normal amounts, you can assume there is something wrong with the cooling system.
  • Engine cuts off. Modern vehicles will shut down to protect the engine when the coolant gets too low.
  • Distinct sweet smell. If you notice this smell, it's likely that the coolant is leaking.

How long should you drive with low coolant levels? Not at all. You could cause serious engine damage when the levels get too low.

Why Is Checking Of Your Vehicles Coolant Level So Important?

Why should you know how to check the coolant level in a car? If you keep the right amount of coolant in the system, you protect the vehicle from sustaining engine damage. The last thing anyone wants is a hefty engine repair bill.

Without the right amount of coolant, the reservoir becomes empty, and there's nothing to extract the heat from the engine. This lack of coolant is what causes a car engine to overheat. When this happens, parts begin to break, and the engine ceases to operate.

Some modern vehicles have systems designed to shut off the car if the coolant becomes too low. These innovative systems help to protect against damage, but you should still know how to check the coolant level in car.


How to Check the Coolant Level in Your Car (& Issues to Look Out For)

You are asking - how to check the coolant level in my car, and we have the steps you need.

Method 1 – Via the coolant reservoir

Park the car on a flat surface and pop open the hood.

  1. 1
    Locate your coolant overflow reservoir.
  2. 2
    You will see terms such as "Full" and "Low," which indicate how much coolant is in the system.
  3. 3
    Use a funnel to fill up the reservoir until it reaches the "Full" status.
  4. 4
    Replace the cap and close the hood.
Method 2 – Via the radiator cap

While this method is less accurate than the previous method, you can still try it if you prefer.

  1. 1
    Park on a flat surface and pop the hood.
  2. 2
    Take off the radiator cap.
  3. 3
    How do I know if my car needs coolant? Do you see coolant? If the system appears full, you don't need to do anything else. However, if the system is empty, complete the rest of our steps.
  4. 4
    Place a funnel in the radiator hole and fill it with the recommended coolant.
  5. 5
    Replace the cap and close the hood.

Whichever method you choose, don't open the radiator or reservoir cap while the engine is hot. The hot engine can cause pressure to build up, which can cause serious injury.

If you aren't sure where to find your reservoir cap, look in the owner's manual. We have a few references for you.

While you are checking the coolant levels, watch for these signs that something is wrong.

  • Leaks
  • Rusty-colored or diluted coolant
  • Oil or sludge in the coolant

How to Top Up Coolant in Your Car (& What You Need)

If your coolant level is a little low, you want to top it off. First, make sure you use the recommended coolant and water ratio directed by the manufacturer. Then, follow these steps.

  1. 1
    Remove the reservoir cap.
  2. 2
    Check the coolant level. If it is too low, you want to add enough to fill it.
  3. 3
    Use a funnel to prevent any spillage.
  4. 4
    Fill it up to the max fill line.

If your coolant system has been completely drained, you might need to take further steps such as bleeding the system. This isn't something that most people should do on their own, but if you are curious, here is a helpful YouTube video.

People Also Ask (FAQs)

Is coolant toxic?

Coolant is poisonous and should always be kept out of the reach of children. It doesn't take much of this substance to cause significant bodily damage or death.

How long does it take to check coolant?

If you know what you are doing, it shouldn't take more than a few minutes. Even if you have to follow a step-by-step guide, you are looking at 15 minutes or less.

Are coolant and antifreeze the same?

Antifreeze and coolant have a lot in common, but the composition is different. Antifreeze contains a concentrated glycol-based substance that must be diluted with water before use. Coolant is a mixture of antifreeze and water, most commonly at a 50/50 ratio.

Should I buy premixed or concentrated coolant?

It depends on what you prefer. If you buy the concentrated, you must mix it with distilled water, which can be a hassle. However, the premixed comes in a larger bottle that is bulkier.

How do I completely empty the coolant?

Just like performing an oil change, there's a plug at the bottom of the radiator that you would pull out to drain the coolant. Once it is empty, you can replace the plug and fill the system, but you will need to bleed out the air.

Why is my coolant low but no leaks? Is it normal for the coolant level to drop?

If you can't find the leak, you might have bigger problems. Talk to a qualified mechanic about damaged cylinder bores, a blown head gasket, manifold leak, or fractured cylinder head.

How long after adding coolant can I drive?

You should always run the engine right after filling the coolant and then check the reservoir again because it might need a little more after the coolant starts to circulate through the cooling system.

How often should you put coolant in your car?

You should add coolant whenever the system gets low. Some manufacturers also suggest changing the coolant every 30,000 miles.

Does my coolant reservoir need to be full?

No, you only want the reservoir to be filled to the appropriate level according to the guides. In most cases, this doesn't mean that the entire reservoir should be filled.


It doesn't take any special skills to check your coolant levels. With our simple guide, you are ready to maintain and care for your engine's cooling system and prevent catastrophic damage down the road.