Low Coolant Level Symptoms, Causes, and How To Fix It

The engine serves as the primary power source for all vehicles that rely on internal combustion engines for propulsion. Similar to the various fluids in the vehicle, engine coolant plays an important part in ensuring optimal performance. Engine coolant, also known as antifreeze, flows throughout the engine, effectively regulating the operating temperature of its various parts. When your car doesn’t have sufficient coolant runs, it produces different signs. This article explains the low engine coolant symptoms, causes, and replacement cost.

What is a Coolant?

Engine coolant, found within you’re the radiator of your car, is a fluid blend of water and antifreeze. Its vital purpose is to safeguard your engine from both overheating during high-temperature conditions and freezing in extremely low-temperature conditions, which can pose significant risks to the engine’s integrity.

The primary role of engine coolant is to effectively absorb the heat generated by the engine components, thereby shielding the engine from potential damage caused by excessive heat or freezing temperatures.

Symptoms of Low Engine Coolant

A low engine coolant produces one or more of the below-given symptoms:

Low Engine Coolant Light Illumination
Heater is not Working
Engine Overheating
Fluctuating Temperature Gauge
Poor Fuel Economy
Sweet Smell of Coolant
Coolant Leak

1) Low Engine Coolant Light Illumination

The latest vehicle models incorporate a dashboard warning light that illuminates when the engine coolant is running low. However, it’s important to note that certain older vehicles may lack this feature.

When the coolant light appears, it becomes essential to proactively monitor and assess the coolant level.

2) Heater is not Working

The engine coolant used in your vehicle’s cooling system is also utilized by the heater. There are different valves employed to regulate the flow of coolant, thereby controlling the temperature.

If your car’s heater is not functioning properly, it could be due to insufficient engine coolant caused by the airlock in the heater core.

3) Engine Overheating

Insufficient coolant in your vehicle can lead to engine overheating, causing the temperature gauge on the dashboard to rise significantly. To address this, it is important to properly inspect the coolant level in your vehicle, as it may be below the recommended level.

4) Fluctuating Temperature Gauge

The fluctuating temperature gauge is one of the clear signs of low engine coolant. This phenomenon occurs when the coolant level is critically low, leading to the circulation of air within the coolant system.

The presence of an airlock surrounding the coolant sensor causes the temperature reading to decrease, which then normalizes once the coolant resumes its flow.

If you observe a significant rise in the temperature gauge on your dashboard, it suggests the possibility of low coolant levels and necessitates an immediate examination to prevent engine overheating.

5) Poor Fuel Economy

One of the most common signs indicating a low coolant level is when your engine starts to consume more fuel than usual, resulting in high fuel consumption or low fuel efficiency.

It’s important to note that poor fuel economy can be attributed to different other problems. Therefore, it should not be instantly assumed that low coolant level is the sole cause unless confirmed by a mechanic or accompanied by other relevant symptoms.

6) Sweet Smell of Coolant

A healthy engine coolant emits a sweet smell. Although it may seem unusual, you can take a whiff of the coolant when purchasing your coolant.

If you detect the smell of coolant inside your car, it indicates a coolant leak. In such conditions, it is crucial to stop the car as soon as possible and seek assistance from a mechanic to rectify the problem.

7) Coolant Leak

It is normal for coolant levels to decrease over time; if you notice a significant and rapid drop in coolant levels, it could indicate a coolant leakage problem.

If you notice any fluid leakage from beneath your car, it is essential to cease driving right away. While the liquid could be any of the various fluids found in your car, it might include vital fluids such as the coolant or engine oil.

In such a situation, it is essential to contact a professional technician before continuing to drive the car for even a minute. Failing to do so may result in significant damage that could require costly repairs.

Causes of Low Engine Coolant Level

The following are the major causes of low engine coolant levels:

External Coolant Leak
Faulty Radiator Cap
Bad Intake Manifold Gasket
Faulty EGR Cooler
Faulty Water Pump

1) External Coolant Leak

One of the most prevalent causes of a low engine coolant level is an external leak. This can occur due to deteriorated radiator hoses or issues with connections. It is essential to have a mechanic inspect and address these leaks promptly to avoid overheating engine issues.

2) Faulty Radiator Cap

Despite its small size, the radiator cap plays a significant role. Its primary function is to establish a secure seal within the pressurized radiator, ensuring that the cooling system maintains the required pressure.

But with regular use, the cap’s seal may degrade, and the spring may wear out, leading to the potential leakage of coolant.

3) Bad Intake Manifold Gasket

In many cases, the intake manifold is designed to cool the intake air using coolant, and it contains different coolant channels. A gasket is located between the cylinder head and the intake manifold to maintain a proper seal.

If this gasket starts to leak, it can result in the engine drawing in and combusting coolant. This can also be identified by the presence of white smoke coming from the tailpipe.

4) Faulty EGR Cooler

Another potential cause of low engine coolant is a crack in the EGR (Exhaust Gas Recirculation) cooler. It’s important to note that all vehicle engines don’t contain EGR coolers, so it is recommended to research whether your particular engine includes one. EGR coolers are typically found in European car models.

If the EGR cooler is faulty and develops a crack, it can lead to coolant leaking into the tailpipe. This coolant leakage can be identified by the presence of white smoke coming from the exhaust pipe.

5) Faulty Water Pump

The water pump of your vehicle is responsible to circulate coolant throughout the engine. If the water pump goes bad or develops leaks, it may lead to coolant loss.

Read More: Bad Water Pump Symptoms and Causes

What to do when the Coolant Level Drops?

If you observe any of the signs associated with a low coolant level, it is important to take prompt action to prevent further complications. Follow the below-given steps if your coolant is insufficient:

Step 1: Do not Panic

Remaining calm is crucial when facing any car problem. Panicking can hinder your ability to handle the situation effectively due to increased stress and a lack of clear thinking.

Step 2: Stop the Vehicle

If you notice signs of overheating while driving, it is important to find a safe location and turn off your car. In some critical situations, you may need to pull over immediately on the highway shoulder.

Step 3: Let the Engine Cool Down

Avoid touching the hood or attempting to open any components to inspect them. Let your engine cool down for a minimum of 12 to 25 minutes. It’s essential to remember that the cooling system and its components will be extremely hot, and attempting to open them can result in injury.

By patiently waiting for the engine to cool down, you ensure your safety and allow for a more accurate assessment and appropriate actions to be taken.

Step 4: Locate the Leaks

Inspect the area surrounding your car for any visible signs of coolant leaks. If you observe significant leaks, it is likely that you won’t be able to continue driving, and you will need to wait for a towing service or roadside assistance.

Step 5: Top off the Coolant

If there are no noticeable signs of a coolant leak, you may attempt to resolve the issue by topping up the coolant. It is important to always carry extra coolant in your car to be prepared for such conditions.

In some cases, some auto professionals may suggest using water as a temporary substitute for coolant until you can reach a service shop, especially if you prefer not to rely on towing services.

However, it is crucial to contact a professional mechanic first and confirm whether using water instead of coolant is acceptable for your specific car. They can provide guidance and advice based on your car’s requirements and conditions.

Step 6: Contact a Mechanic

If a trusted mechanic is in your contact, it is advisable to contact them immediately and explain the situation. Your mechanic is familiar with your vehicle and can provide you with specific instructions on what steps to take next based on their expertise.

FAQ Section

Why is engine coolant important?

Engine coolant is important because it assists in regulating the engine temperature, preventing it from overheating. It absorbs and dissipates heat generated by the engine, ensuring optimal operating conditions. Additionally, coolant helps prevent corrosion, lubricates various components, and protects against freezing or boiling in extreme temperatures.

Can I drive with a low engine coolant level?

Driving with a low engine coolant level is not safe. It can result in the formation of airlocks in your coolant system and lead to severe consequences such as engine overheating, potential damage to expensive engine components such as the engine block, fuel injector, or even complete engine failure.

What are the signs of low coolant?

Common signs of low engine coolant include low coolant warning light illumination, poor engine performance, poor fuel economy, steam coming from the hood, and engine overheating.

What is the major cause of low coolant levels?

Low coolant levels are typically caused by coolant leaks, which can be identified and repaired relatively easily. However, neglecting to address these leaks and continuing to run the engine with low coolant can result in overheating and critical damage to the engine.

What happens if a car runs out of coolant?

If your engine has insufficient coolant, it will start to overheat. This poses a significant risk of engine damage and potential engine failure. To avoid such issues, it is important to regularly check the coolant level in the radiator and address any coolant leaks promptly.

How long can a car last without coolant?

Coolant is essential for your vehicle’s proper functioning, and driving without it is not advisable. Without sufficient coolant, your engine will quickly overheat, potentially leading to engine damage. In some cases, modern vehicles have safety mechanisms like limp mode that automatically shut off the engine to prevent further harm.

Does coolant affect acceleration?

If you notice a loss of acceleration or poor fuel economy, it may be an indication of low coolant. Proper coolant circulation is crucial for the engine to work effectively, and when coolant levels are inadequate, the engine may not receive the necessary cooling, and its performance can be affected.

Can low coolant cause rough idle?

Yes, an insufficient coolant may lead to a rough idle. The engine coolant is responsible to maintain the engine’s operating temperature and prevent it from overheating. The low coolant levels may cause engine overheating, which may badly impact the engine’s performance and cause a rough idle.

Written By

Engineer Rahela

Rahela is the owner and main author of Mechanicalspecial. She is an automotive expert writer. She have over four years of experience in the automotive writing niche and have completed over 700 pieces of content from 40 projects. She have good knowledge and skill in vehicle repairing, all mechanical work, car upgrades and maintenance.