6 Low Coolant Symptoms + Cost to Fix

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low coolant symptoms

If you’re a car owner, you know that it’s important to keep your car’s coolant system in good condition. Not only is low coolant bad for your engine, but it can also cause some major headaches down the road. Here are six common symptoms of low coolant and the average cost to fix them.

Keep an eye on these warning signs, and make sure to top off your coolant levels before they become a bigger problem!

Cooling System of the Car

The primary purpose of the cooling system in a car is to remove excess heat produced during the combustion process. Combustion is a high-temperature process. Local temperature near the exhaust valve and ignition areas can go as high as 700 degrees Celcius.

The coolant circulates in water jackets around the engine block. It prevents overheating by removing the residual heat produced during combustion.

There are two types of cooling systems used in cars:

Air Cooled

Air Cooled engines have fins around their surface. Fins enhance the process of heat removal. It is efficient for small engines but is not recommended for larger engine blocks.

Fluid Cooled

Fluids such as water, propylene glycol, or a mixture of both, run in the fluid channels around the engine of your vehicle.

Most modern cars utilize a fluid cooling system as it is more efficient and more effectively removes heat produced in the engine.

What Can Cause Low Coolant Levels?

Part of coolant is indeed water that can evaporate due to high temperature. But since it is a closed system so ideally, no vapors should escape the cycle. There must be some leak if you have low or no coolant.

There can be three types of leakage from the coolant system:

From Radiator Cap

The radiator cap is the only part of the cooling system that is opened and closed frequently. Sometimes it is left loose that can cause coolant to escape. Or at times it is just due to a faulty radiator cap.

External Leaks

The coolant passes through a series of external components before entering the main engine block. These components include the water pump, hoses, and radiator. If the connection between any of these components is weak, the coolant will leak.

Internal Engine Leaks

Coolant has to pass through the engine to carry away the residual heat. There can be internal engine leaks due to worn-out components. Water jackets are supposed to be sealed, but sealing might be compromised if there is a leak. Hence, the coolant can enter the core engine components.

Symptoms of Low Engine Coolant

Following are the signs of low coolant:

  1. Engine Overheating
  2. Automatic Engine Cut off
  3. Poor Fuel Economy
  4. Rising Temperature Gauge
  5. AC Blowing Constant Hot Air
  6. Distinct Sweet Smell

Let us take a closer look at the warning signs of low coolant:

Engine Overheating

The function of the coolant is to remove excess heat produced during the combustion process. If you have a low coolant level, then heat removal will not be efficient.

Hence, the local temperatures increase when heat is not removed and the engine overheats. You can even have a blown head gasket.

Automatic Engine Cut off

When you have low coolant in your vehicle the engine might shut off automatically. The culprit again is the high temperature of the engine. The engine is set to work at the right temperature.

When the temperature goes above or below that mark the engine would automatically cut off power to prevent damage.

You may also experience difficulty starting the vehicle when the engine coolant is low.

Poor Fuel Economy

The high temperature of the engine can also drop your car’s fuel efficiency.

When your engine’s temperature is high, the coolant pump has to work more to remove the extra heat. This puts a lot of pressure on the water pump. Leaving the strain on the pump aside, it consumes more power from the engine to increase heat removal rates.

If the engine has to produce more work, it will consume more fuel. Hence, the dip in fuel mileage.

Rising Temperature Gauge

The dashboard warning light is the clearest sign that something is wrong with your car. A temperature gauge is present in the engine of your car. It measures temperature and conveys this reading to the head dashboard.

The output display of the temperature gauge is present on the dashboard of most cars. This temperature gauge crosses the halfway mark if the engine has overheated beyond optimum levels.

Keep an eye on this temperature gauge. It is a direct warning of low engine coolant.

AC Blowing Constant Hot Air

The vehicle’s cooling system will not work properly if the coolant system is not fine. An overheated engine can cause the thermostat valve of your car to trip. It will compromise the working of the AC. It can also cause your car’s AC to blow hot air instead of cold.

The AC and the interior heating system of the car also pose problems if you have low engine coolant. The car’s heater utilizes the heat removed by the coolant. In case it does not provide the required heat, you get poor performance of the heater.

Distinct Sweet Smell

The pressurized coolant can leak inside the car via AC ducts. You might feel a distinct sweet smell inside the passenger compartment of your car. It is the smell of the coolant. If you observe this symptom, visit a car care professional to resolve it.

Coolant Refill Cost

Coolant refill can cost you somewhere between $90 and $180 depending upon the make and model of your vehicle. The coolant itself is quite cheap. You can purchase a bottle of coolant for $20 or $30.

The remaining part is the labor cost. A skilled mechanic can charge you $60 to $150 for a coolant refill. Pouring coolant is not an issue but the main task is to flush out the old coolant and check for leaks.


The cooling system is the backbone of your car engine. The car engine can of itself do nothing if the cooling system is not working.

And coolant is the heart and soul of the cooling system. You will receive external and internal warnings if you have low engine coolant. The internal heating system and cooling system of the car are compromised. Low engine coolant can cause your engine to overheat. It can hurt the fuel economy of your car as well.

Low engine coolant is very harmful to your car and its systems, to say the least. Hence, you must not take it lightly. If you observe the signs of low engine coolant then you must refill it immediately.

Frequently Asked Questions

Is coolant the same as antifreeze?

Yes, engine coolant and antifreeze are the same things. As the same fluid is responsible for removing the excess heat produced during the combustion process and the same coolant keeps the radiator from freezing in extremely cold weather.

Can you refill your engine coolant yourself?

Yes, you can refill your engine coolant. Once established that you have low engine coolant then you need to flush out the old coolant and pour in the new one. The process is not as simple as that but still, you can manage it with the help of a few tutorials.

Is it possible to get a false dashboard warning light for low engine coolant?

Yes, it is possible to get a false dashboard light for low engine coolant. Sometimes the coolant level sensor is not functioning properly. Hence, it can raise false alarms of low engine coolant.

Can low coolant cease your car’s engine?

Yes, low coolant can very well cease the engine of your vehicle. If you have low engine coolant the excess heat is not removed. It can cause irreparable damage to the engine parts. Excess heat can also cause the head gasket to blow. In the worst-case scenario, the engine of your car may cease to function as well.

Is engine coolant the green fluid leaking under your car?

Yes, propylene glycol mixed with water can give it a slightly yellow or greenish color. The green or yellow fluid leaking under your car is definitely the engine coolant.

Can a coolant leak cause a misfire?

Yes, a coolant leak can cause your engine to misfire in two ways. If it internally leaks into the engine pistons, it can affect the combustion process that might end up misfiring. Second, due to extreme temperatures inside the engine block, the ignition might take place way before the desired location. This can also lead to misfiring as well.

How often you should top up your coolant?

Ideally, you should top up the coolant of your car every 18 to 24 months. Even if there is no leakage the efficacy of the coolant is somewhat compromised after this interval. However, in case of leakage, you must refill it ASAP.

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