Coolant Leak: Causes, Symptoms, & How to Fix It

The efficient working of the engine is very important for the efficient operation of the vehicle. The engine coolant or antifreeze plays a big role to prevent your engine from overheating and also maintains the normal temperature of the engine.

The leaking or low level of the coolant is not a good thing. This article mainly explains the signs and causes of the coolant or antifreeze leak, the coolant leak repair cost, and how to fix it.

What is a Coolant?

Coolant is an engine fluid that is responsible for regulating the temperature of an engine. It protects the engine from overheating or freezing. The coolant is also known as “antifreeze.”  

The main function of an engine coolant is to absorb the heat of the engine parts and prevent the engine from damage due to overheating or freezing.

Coolant is usually a mixture of antifreeze and water, absorbs the heat produced by the engine, and expels it through the radiator.

It puts in the car radiator. It behaves differently in summer and winter. In winter, it acts as an antifreeze and stops the radiator liquid from cracking and freezing. While in summer, it maintains the engine temperature and prevents your engine from overheating.

What Is a Coolant Leak?

A coolant leak is a situation where the coolant escapes from the cooling system due to a leak or damaged parts.

The coolant or antifreeze leaks may cause due to multiple reasons such as a blown head gasket, damaged hose clamps, radiator hoses, and damaged heater core.

As the coolant leaks, the coolant level in the radiator becomes lower than the desired level, which can contaminate the engine oil, damage the cylinder head, overheat the engine, or failure of the engine.

Symptoms of Coolant Leak

A sufficient level of engine coolant is very important for the efficient working of the cooling system. Sometimes, the coolant level goes down because of leaks and some other causes. As your car coolant level becomes low than normal, your car starts producing different symptoms.

The following are the symptoms of low coolant or coolant leaks:

• Coolant on the garage floor
• Temperature gauge show high temperature 
• Low coolant level
• Coolant smell
• Puddle of coolant
• Illuminated coolant warning light
• Bubbles in radiator 
• Engine overheating
• Quick reduction in coolant level
• Poor engine performance 
• Smoke from the engine

#1. Visible Coolant on Garage Floor.

The visible coolant on the garage floor (or where you park your vehicle) is a most common symptom of a coolant leak.

A healthy coolant has pink, orange, or light green color. It has a sweet smell. As you observe a coolant leak, you must first clean it because it is toxic to pets and humans.

#2. Temperature Gauge Show High Temperature.

The temperature gauge measures the engine temperature. It is located on the car dashboard. Very low fluctuations in the temperature gauge are normal, but sudden or large changes in temperature usually indicate a problem.

If your temperature gauge is showing a high temperature, it means your vehicle has low engine oil, low coolant level, or an issue with the cooling system.

Read More: Low Engine Oil Symptoms and Causes

#3. Low Coolant Level.

The vehicle contains an expansion tank that contains additional coolant in case the engine coolant level becomes very low, and the vehicle fills it back from the reservoir itself.

Check the coolant level in the expansion tank. Measure the coolant level; if it is low, it means your coolant may be leaking.

#4. Coolant Smell.

The smell of the healthy engine coolant is very sweet. It may sound strange but smell it next time as you buy a coolant bottle. If your car coolant starts to leak, you may smell it in the passenger compartment. In such a situation, immediately stop your vehicle and contact a professional mechanic to fix the issue. 

#5. Puddle of Coolant.

This is one of the most common signs of coolant leaks that you may also observe when you remove your vehicle from a place after a long time.

When your car has a coolant leak, and you have parked it in one place for a long time, you may find a large puddle of coolant under your car. The flow of refrigerant leaks also plays an important role here.

#6. Illuminated Coolant Warning Light. 

The latest vehicles have different warning signs and symbols on the dashboard. The latest cars have a coolant warning light. This light is located on the vehicle dashboard.

When the coolant level in the coolant tank goes down than the desired level, the coolant light starts glowing. 

If your vehicle warning light is illuminating, it means you have a coolant leak; due to that, your coolant level has gone low.

Read More: Causes of Check Engine Light Illumination

#7. Bubbles in Radiator.

In normal conditions, the coolant expansion tank and radiator pipe are well sealed. Therefore, air bubbles should be not there. In case of a coolant leak, combusted exhaust gases emitted by the engine can enter the radiator or expansion tank.

When the combusted gases enter the radiator, they generate bubbles inside the radiator. As you see bubbles in your expansion tank or radiator, it means you have a coolant leak. When you observe air bubbles in your car’s coolant reservoir or radiator, you must immediately contact a professional.

#8. Engine Overheating.

As we discussed above, the main function of the coolant is to prevent the engine from overheating. If your car engine is overheating, it means you don’t have sufficient coolant due to that your cooling system not working properly and the engine overheating.

Read More: Engine Overheating Symptoms and Causes

#9. Quick reduction in Coolant Level.

If you notice a sudden drop in the coolant level, it is 100% certain that you have coolant leaking.

#10. Poor Engine Performance.

A sufficient level of coolant ensures the efficient performance of the engine. When it is leaked, your engine starts to overheat which leads to poor engine performance. 

#11. Smoke from the Engine.

If the coolant is leaking near hot engine parts, it may evaporate and create steam or smoke under the hood.

Read More: How to Add Oil to Car Engine?

Causes of Coolant Leaks

The coolant leak can be caused because of many reasons, such as a blown head gasket, radiator cap leak, hoses leaks, and many other factors. Let’s have a look at the causes of the coolant leaks:

1. Hole In the Radiator
2. Damaged Hoses
3. Leaky Radiator Cap
4. Blown Head Gasket
5. Water Pump Failure
6. Damaged Expansion Tank
7. Damaged Heater Core

#1. Hole In the Radiator.

As we know, an engine generates extreme heat. Therefore, car engine parts have to withstand a lot of wear and tear and extreme temperatures and pressure.

With the passage of time, the hose gets weaker, and debris and contamination can build up inside the hose. When the debris makes contact with the radiator water, it may produce corrosion inside the radiator. This corrosion may create a hole in the radiator and cause coolant leaks.  

Solution: Continuously inspect the radiator and prevent it from corrosion. As you see corrosion build up, immediately remove it so that you can save your radiator from an expansive repair.

#2. Cracked or Damaged Hoses.

The hoses play a big role in the cooling system. They connect the water pump to the engine and the engine to the radiator. The coolant flows inside the hoses. They are installed under the hood of the vehicle. 

With time, the hoses become stiff and brittle. A cracked or damaged hose can cause the coolant leak.

Solution: Inspect the vehicle hoses before driving the vehicle. Ensures the proper maintenance of your car hoses and replaces them on time. 

#3. Leaky Radiator Cap.

Your car radiator has a small cap, but it performs a big role. The radiator is under extremely high pressure, and the cap serves to create a tight seal that maintains the appropriate pressure of the cooling system.

With time, the radiator cap seal becomes weaker, or the springs can wear out, leading to coolant leaks.

Solution: You must continuously inspect the radiator cap and replace it immediately in case of a worn or damaged cap.

Read More: Working of Cooling System

#4. Blown Head Gasket.

A head gasket plays a vital role in the efficient working of the engine. It is located in between the engine block and the cylinder head.

It provides an efficient seal between the engine block and cylinder head as well as stops the leakage of engine oil and coolant. It has the ability to bear extreme temperatures and pressure.

The head gasket has the responsibility to maintain desired temperature and pressures inside the engine. The main function of the head gasket is to maintain the separation between the coolant and engine oil.

The worn or blown head gasket is one of the major causes of coolant leaks. Due to the blown gasket, engine oil, and coolant cannot be separated. The coolant will mix with engine oil and burn into the combustion chamber, which may cause engine failure.

Solution: Regularly inspect the head gasket of your engine and replace it before its expiry date.

Read More: Working and Function of Head Gasket

#5. Water Pump Failure.

A water pump is also a most important part of the engine cooling system. It ensures proper coolant circulation throughout the cooling system. The engine power is utilized to drive the pump. Damage in the water pump may lead to a coolant leak.

As the water pump fails, it doesn’t properly circulate the coolant due to that engine overheats.  

Solution: Check the pump before driving the car. If your car has a failed pump, first replace it and then drive the vehicle.

#6. Damaged Expansion Tank.

An expansion tank uses to transfer coolant to the car radiator. It is made of plastic. A rubber hose uses to connect it to the radiator. It transfers or gets coolant to and from the radiator as the engine cools down or warms up.

With time, the plastic of the tank becomes weak, and the parts attached to it also weaken. Due to this weakness, the tank or cap may crank, which may cause of coolant leak.

Solution: Inspect the expansion tank regularly and ensure its proper maintenance.

#7. Damaged Heater Core.

The heater core gets heat from the radiator coolant and transfers this heat inside the car. This heater core may also cause of coolant leak. In such conditions, there may be liquid in the plastic case at the heater’s core bottom.

Solution: Regularly check and maintain the heater core.

Read More: Working of Heater Core

How to Find a Coolant Leak?

As we discussed above, coolant leaks may occur due to different reasons. If your car coolant is also leaked and you want to find the leakage reason then follow the below-given steps to find it:

1. Run the Vehicle: To find leaks, first run the vehicle until it is fully warm and then park it in a clean area.
2. Leave the engine for cooling: Switch off the vehicle engine and wait for a few minutes until it fully cools. The engine and coolant have very high temperatures and pressures when the vehicle runs. If you remove the radiator cap or recovery tank cap in warm engine conditions, the hot coolant may severely harm your skin.
3. Engine Compartment Inspection: Open the hood and inspect the engine compartment. During this inspection, you should also smell around to find if you can spot where the coolant smell is coming from.
4. Find the Coolant Puddle: Look underneath your vehicle for a fresh puddle of coolant. If you don’t see a puddle and you are still smelling the sweet odor of antifreeze, climb down and look under the vehicle to see if it’s wet or not.
5. Inspect the complete system: Check the hose connected to the engine compartment (inspect the hose ends from where they connect to other parts), the area around the radiator cap, and the internal side of the radiator to find the signs of coolant. If there are no clear signs of coolant leaks, inspect the entire engine compartment. This leak may have come from anywhere under the hood.
6. Heater Core Leak: If the antifreeze smell is more inside the car than outside, it means that the problem is with your car heater. The heater uses a “core” like a radiator to deliver heat inside the car. If your car carpet is humid or there is moisture on the windows, it means that your car has a leaking heater core. Since the heater is part of the air conditioning system and is integrated behind the dashboard. Therefore, a leak in the heater core is very tough to find and even harder to repair.
7. Inspect the Hose: You can check the condition of the hose to see if there is a leak around the hose. Bad hoses can also cause coolant leaks. If you find that the hose is leaking near the clamp, use a screwdriver to tighten the clamp.

How To Fix a Coolant Leak

The coolant or antifreeze is not much hard to fix. As we discussed, your radiator antifreeze may leak because of different reasons. Follow the below-given different methods to fix the coolant leaks:

• Use eggs 
• Replace the damaged hose clamps
• Replace the damaged hose
• Replace the faulty radiator 
• Replace the expansion tank
• Replace the damaged cap of the expansion tank

#1. Use Eggs.

If you are on the way and your radiator coolant is leaked, first try to search the nearest repair workshop. If there is no nearest workshop and your radiator is leaking coolant quickly then buy some eggs and put them into the radiator.

This option is only suggested if no other option is available.

1. Stop your vehicle on the side of the road and turn off the engine.
2. Wait for 6 to 15 minutes until your engine cools.
3. Lift the hood and remove the cap of the radiator.
4. Crack and put three eggs inside the radiator reservoir.
5. Now inspect the leak, whether it has been stopped or not. If leakage is not stopped, crack more eggs into the reservoir until it blocks.

#2. Replace the Damaged Hose Clamps.

Sometimes, antifreeze or coolant may leak due to old, worn, or damaged hose clamps. In such a case, you need to replace your vehicle hose clamps.

To replace a hose clamp, follow the below-given steps:

1. Turn off the car engine and wait for 6 to 15 minutes until your engine cools.
2. Lift the hood and unscrew the radiator cap.
3. Find the worn or damaged hose clamp.
4. According to the hose clamp location, you may need to drain some antifreeze. Put the vessel under the hose and drain as much fluid as needed to access the hose and clamp.
5. Unscrew the worm or damaged clamp. If you can’t unscrew it, you may also cut it.
6. Install the new clamp onto the untied hose.
7. Tightly screw the hose clamp. 
8. Add the new antifreeze into the radiator reservoir and reinstall the radiator cap.

#3. Replace the Damaged Radiator Hose. 

The hose is the most vital part of the engine cooling system that connects the parts of the engine. With time, the vehicle hoses are damaged or worn. In such conditions, they may cause of coolant leak, and you may need to replace them to fix the coolant leak.

To replace a hose, follow the below-given steps:

1. Turn off the car engine and wait for 6 to 15 minutes until your engine cools.
2. Lift the hood and unscrew the radiator cap.
3. Find the worn or damaged hose clamp.
4. According to the hose location, you may need to discharge some antifreeze. Put the vessel under the hose and discharge as much fluid as needed to access the hose and clamp.
5. Remove the hose clamp on both ends of the hose.
6. After clamp removal, remove the old or damaged hose.
7. Install the new hose and tightly screw the hose clamps on both ends.
8. Add new antifreeze into the radiator reservoir and reinstall the radiator cap.
9. Now inspect and ensure that the coolant is not leaking.

#4. Replace the Faulty Radiator.

A radiator is a place that bears extreme pressure and temperature. Sometimes, the coolant leak occurs due to a damaged or old radiator. In such a condition, you need to replace it immediately.

What is the color of the car engine coolant?

The engine coolant has the following different colors:

COOLANT TYPE	INHIBITOR TECHNOLOGY	COLOR	VEHICLES
Si-OAT (Silicated HOAT)	Silicates & Organic Acids	PURPLE	Porsche, VW, Audi, Mercedes-Benz, others
Mini, Tesla, Volvo, BMW, and others	Phosphates & Organic Acids	PINK / BLUE	Hyundai, Honda,  Nissan, Toyota, KIA & other Asian vehicles
HOAT (Hybrid OAT, Phosphate-free)	NAP Free	TURQUOISE	Porsche, VW, Audi, Mercedes-Benz, and others
HOAT (Hybrid OAT)	Silicates & Organic Acids	YELLOW	European, Chrysler, Ford
OAT (Organic Acid Technology)	Organic Acids	ORANGE	VW, Saab, GM
IAT (Inorganic Additive Technology)	Silicates	GREEN	Older Vehicles

How much does it cost to fix a coolant leak?

The cost of an engine coolant leak fix depends on many factors, such as the nature of the leak and the area where you live.

The average cost of a coolant leak fix is from $500 to $800. If you notice the leak early on, then the fixing cost will be low, and you may need to pay from $80 to $150. 

The below-given table represents the cost of the coolant leak fix for different workshops:

Auto Center	Price
Amazon	$ 100 to $230
Midas	$120 to $590
NAPA	$210 to $850
Mr Tire	$130 to $660
Your Mechanic	$150 to $910
Walmart	$90 to $250

FAQs.