Driver's Guide

How Much Coolant Does My Car Need When Empty?

Changing your engine coolant is self-service maintenance that does not require a mechanic. But how much coolant does your car need when empty? Well, I will disclose the exact amount of coolant your vehicle needs.

Most car cooling systems hold around 5 liters and engine coolants are sold in 1 – 20 liters containers, so it’s easy to purchase the exact amount that you want. When empty and depending on the capacity of your car’s coolant, it should need around 5 liters of coolant fluid. Alternatively, you can get more information from your driver’s manual, workshop, or inquire from your car manufacturer online.

It also depends on where your car coolant is located. The coolant reservoir may be located under the bonnet of your vehicle. Typically, the reservoir is marked with the minimum/maximum markers in modern cars. Note that you want to be sure that it does not exceed the maximum market when applying the coolant.

If you have a high-performance car, then you need special coolants. Be sure to check out our recommendations for high-performance cars.

You would be adding the coolant to the reservoir and not the radiator. For older cars with no coolant reservoir, the coolant goes to the radiator as a mixture. If you want to go through our list of recommended coolants for your radiator in hot weather and to keep your car in optimal performance, check out our list.

how much coolant does my car need when empty
Car coolant compartment

Is It Normal for Coolant to Get Low?

It is not normal for coolant to get low, but it is not normal when it drains faster. Faster coolant drainage could indicate leakage in the engine, hoses, or the radiator and must be replaced to avoid overheating while driving. Moreover, when there is a blockage or the thermostat is set too high, the coolant heats to a boiling point causing the vapor to exit the car faster, and it reduces the coolant level.

Can You Drive with Low Coolant?

No, you cannot drive with a low coolant. The coolant cools the engine of your vehicle, which keeps the car going and it eliminates fire outbreak. If you drive with low coolant, the fuel and air mixture produce lots of heat which cannot be dissipated. Of course, it can damage your engine, and it drains more fuel. Meanwhile, you can follow these steps to save fuel in a petrol car.

What Are the Signs of Low Coolant?

When coolant is low, it affects the internal temperature of your car’s engine that is protected by the antifreeze. To know that your coolant is empty, the temperature gauge should rise because your engine will heat up rapidly. Secondly, if you have a modern car, the engine cut-off feature would be enabled, and the car would cease. Thirdly, low or empty coolant triggers the malfunction illumination light that we mostly refer to as the ‘check engine light.’

How Much Coolant Does My Car Need When Empty?

As explained earlier, most car cooling systems hold around 5 liters  In some vehicles, the coolant recovery system is pressurized, and they carry the radiator pressure cap instead of the normal cap. If you have an older vehicle, you will not find the coolant reservoir, so you have to open the radiator cap to add coolant.

Before you add the coolant, make sure the radiator cap is off. Now, tighten the drain plug and fit the lower radiator hose back. You can also flush the cooling system by refilling it with plain water. Note that it is improper to add coolant while the engine is still hot.

Does your coolant reservoir have to be full? Since the reservoir is vital for your car’s cooling system, it should be full to an extent at least. The reservoir stores excess coolant fluid until the engine needs it. So, while your engine is off, the reservoir should be at least 30% full.

Do You Put Coolant in the Radiator or Reservoir?

Older cars do not feature the coolant reservoir, so you mix and add the radiator coolant. If your coolant level is empty, add coolant to the coolant reservoir in a modern car. Mix the concentrated coolant with distilled water, and be sure the mixture is 50/50. When the coolant level rises to the cold fill line, replace the cap.

What Happens if You Overfill Your Coolant Reservoir?

If you overfill your coolant after it becomes empty, the pressure in the reservoir will increase, and the tan cap may open, making way for hot coolant to escape the engine. It is because an overfilled coolant reservoir provides too little to no space for heated coolant to expand.

Can I Mix Different Brands of Coolant?

Yes, you can mix different coolant brands; however, it must be the same kind of coolant. You can also weaken corrosion if you mix a significant amount of one type of coolant with another. For instance, mixing IAT (Inorganic Additive Technology) with HOAT (Hybrid Organic Acid Technology).

How Long Can You Run an Engine Without Coolant?

If the engine is heated, you should not drive your car without a coolant. However, at a cold state, you can run the engine for about 5 minutes, after which it overheats and can cause damages.

Is It OK to Add New Coolant Without Draining the Old?

Yes, you can top off the coolant without draining the old one. Make sure the coolant level remains in the same place. If it does down, there is a leakage, or the coolant is being burned up in the cylinders. So, you can add more coolant to the already existing coolant.

Can I Drive After Adding Coolant?

You can run the engine after adding coolant but do not add coolant while the engine is hot.

How Long Does Coolant Last in a Car?

The average duration of coolant in a car depends on the type of coolant and the vehicle’s make and model. Typically, silicate coolant lasts up to 2 years or 30,000 miles, while extended drain coolant lasts up to 5 years or 100,000 miles. Note that you can differentiate between coolants from the coolant color.

The volume of Engine Coolant

Some cooling systems can hold around 5 liters of coolant. Typically, auto repair shops sell engine coolant in 1-20 liter containers, which you can select the liters you need for your vehicle. You can tell how many liters you need by looking up your number plate on websites such as,, and to discover the coolants to use in your vehicle.

How Much Does It Cost to Replace Coolant in a Car?

The cost of replacing coolant or flushing radiator in a car ranges between $100 and $150 at most mechanic shops, depending on your location. Some auto repair shops offer incentives and bonuses, which means you could be replacing coolant for your vehicle at less cost. Note that the estimated cost I provide here does not include tax and other charges.

Meanwhile, if you are selling your car and the buyer requests proof that you refilled the coolant recently, you can create an auto repair receipt indicating coolant refill and issue it to them.

Latest posts by Bernard Juchli (see all)

Bernard Juchli

Bernard Juchli is an experienced racer, mechanic and team owner who trusts Avon Tyres.Bernard is the lead driver and force behind his Big Dog Garage Race Team. He is the General Manager and Chief Mechanic of Jay Leno’s Garage. Bernard and his crew of seven are responsible for all repairs, restoration and fabrication of Jay’s incredible automobile and motorcycle collection.

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