What are the Signs of Cooling System Failure? | Engine Cooling System Problems and Solutions

A cooling system plays a big role in the proper working of the engine. It prevents the engine from overheating and maintains its temperature. Therefore, the proper maintenance and repair of the cooling system are very important for its efficient working. A failed or bad cooling system generates different signs. As you observe the signs of cooling system failure, you must immediately fix the problem. This article mainly explains the bad engine cooling system symptoms and causes.

What is a Cooling System?

A cooling system is a combination of different parts that maintain the normal operating temperature of the engine and prevent it from overheating. 

engine cooling system working

Causes of A Bad Cooling System 

An engine cooling system goes bad because of different problems. The following are the most common problems that cause a cooling system failure:

  • Water Pump Failure
  • Radiator Hose Leaks
  • Coolant Leak
  • Low Coolant Level
  • Faulty Thermostat
  • Failed Temperature Gauge
  • Frozen Coolant

1) Water Pump Failure

Damaged Water Pump

The car engine is housed under a massive metal hood for better aerodynamics and fuel permanence, so you can’t depend on air flow to keep it cool. Therefore, a liquid coolant is utilized that flows through a series of hoses to maintain the normal temperature of the engine. A water pump is employed to circulate this coolant.  

The engine power is utilized to drive the water pump. The main function of this pump is to circulate the coolant through the engine water vents.

If your water pump is damaged, coolant cannot flow through the engine system, and the engine will instantly overheat. Therefore, it is known as the heart of the cooling system.

Solution: Inspect the water pump before driving the vehicle. In case of failed water pump, immediately replace it with the new one for the efficient working of your engine.

Read Also: Different Types of Water Pumps

2) Radiator Hose Leaks

The rubber hoses make a connection between the water pump, radiator, and engine. The liquid coolant flows from the water pump to the engine and the engine to the radiator through the hoses.

As these hoses leak, the coolant couldn’t properly transfer from the water pump to the engine or engine to the radiator. If coolant does not properly circulate throughout the engine system, it will not absorb the engine heat. In this way, the leaking hoses cause the engine to overheat.  

Solution: As you observe the hose leak, install the new hose. The radiator hose becomes lighter with time, so please replace it regularly.

3) Coolant Leak

coolant leaks

Liquid coolant can escape from the engine cooling system. Regular inspection can detect external leaks as the coolant leaks from the system.

Internal leaks can cause some coolant to leak into the engine oil due to a cracked engine block, cracked cylinder head, loose cylinder head, or poor cylinder head gaskets.

If the coolant leakage level is extreme, the lubrication level in the oil pan will increase. Internal leaks can also generate a white plume of vapor in the exhaust.

Solution: Continuously inspect the coolant passages and maintain them on time. As you see a coolant leak, immediately fix it so that you can prevent yourself by an expansive repair.

Read More: Coolant Leak Symptoms and Causes

4) Low Coolant Level

Coolant level

The low coolant level is one of the most common reasons for engine cooling system failure. The coolant leak can also cause of shortage or a low coolant level.

Solution: Check the coolant level of your car before driving. If it is low, add more coolant up to the required level.

5) Faulty Thermostat

Bad Thermostat

Thermostat failure is another major problem with the cooling system. A thermostat is a mechanical unit that helps to regulate the engine temperature and handles the amount of coolant that can flow through the radiator. It acts as a valve that closes and opens for the coolant.

As the engine warms up, the thermostat opens fully for maximum cooling. In the case of a cold engine, it remains switched off, allowing the engine to reach the optimum temperature more quickly.

Therefore, the on-time proper opening and closing of the thermostat are very important for the proper operation of the cooling system. A faulty thermostat can’t open or close properly, avoiding heat transfer from the engine to the coolant and causing the engine to overheat and fail.

Solution: Inspect the thermostat and replace it if needed.

6) Failed Temperature Gauge

Temperature Gauge, causes of bad cooling system

The vehicle dashboard has a temperature gauge that shows the current temperature of your vehicle engine. If it damages or fails, you will be unable to read the exact temperature of the engine. Therefore, the accurate reading of the temperature gauge is very important for the proper operation of the engine.

 Solution: If your vehicle temperature gauge has gone defective, you must repair or replace it as soon as possible. A simple way to check a defective temperature gauge is to measure the temperature of the water tank cooling water and then measure the same water temperature with a thermometer. After taking both readings, compare both readings.

7) Frozen Coolant

The water has a very low freezing point. Therefore, it can freeze in the cooling system and create a problem. Your coolant can freeze if you park your vehicle in a place where the temperature is less than the freezing point.

As your coolant freezes, it can completely fail the cooling system or can severely damage any part of the system.

Solution: Check the cooling system for possible damage from frozen coolant before driving the car. If your coolant has been frozen, turn on the engine and wait for a few minutes until the coolant converts into liquid form, then drive the vehicle.

Read More: Working and Types of Cooling System

Signs of Cooling System Failure

As the engine cooling system fails, it generates different signs. The following are the most common symptoms of a bad engine cooling system:

  • Low coolant level
  • Engine overheating
  • Frozen coolant
  • Black or dark color of the coolant
  • Problems in engine start
  • Decreasing gas mileage
  • Temperature gauge warning light

1) Low Coolant Level

coolant level, symptoms of bad engine cooling system

Coolant is one of the most important parts of the cooling system. It plays a big role in cooling the engine. Therefore, the proper amount of coolant in the radiator is very important. You must check the coolant level regularly. You should check the coolant level before driving the vehicle.

If the liquid level is low, you may just need to add more liquid. Alternatively, if your coolant level goes down very quickly, it is a sign of a coolant leak or a bad cooling system. In this condition, drive your vehicle to a technician and ask him to repair it.

2) Coolant Color

The color of a healthy coolant is light green/yellow. Inspect the color of your car coolant, and it must be very light green/yellow and translucent in appearance.

If your coolant color has been converted into dark or is full of dust particles, this is a symptom of a bad cooling system. In this condition, you should change the coolant or flush the fluid completely, or change the components of the cooling system.

3) Noise

The cooling system can be noisy due to dry bearings, loose pump shaft pulleys, loose shaft impellers, or two large end plates on the shaft. Some pumps require the addition of a special water pump lubricant to the coolant to eliminate operating noise.

4) Engine Overheating

engine overheating

The main function of the cooling system is to prevent engine overheating. In case of a bad cooling system, the engine temperature doesn’t regulate properly while it’s running. Due to this problem, the engine overheats. If your engine is overheating, it is a sign of a failed cooling system.

The engine overheating may badly damage the parts of the engine or cause complete failure of the engine.

Therefore, as you observe overheating issues, immediately inspect your cooling system and fix the problem.

Read More: Engine Overheating Symptoms and Causes

5) Coolant Leak

As you observe a coolant leak, immediately fix it. The coolant leak may cause the complete failure of the cooling system or engine.

6) Engine Not Starting

If you have a bad electrical system, ignition, alternator, or battery, then your engine will not be started. The engine couldn’t be started because of a bad cooling system.

7) Poor Gas Mileage

Each vehicle has a specific temperature range in which the engine attains maximum fuel efficiency. If your engine temperature becomes more than the normal temperature, then you will see a reduction in gas mileage. This is a sign of a cooling system failure.

8) Temperature Warning Light

Your car dashboard has a temperature gauge that tells the temperature of your car engine. As the temperature gauge suddenly trips into the red zone, it means that your cooling system is not working properly and the engine is overheating. In such a situation, call a technician and ask him to fix the problem. 

In case of a bad cooling system, you may see the illuminated check engine light on your dashboard. 

How To Test A Cooling System?

FAQ Section

Why goes a cooling system go bad?

Following are the most common reasons due to why your good cooling system goes bad:

  1. Insufficient repair or maintenance of the cooling system
  2. Insufficient amount of coolant in the car radiator
  3. Coolant leak
  4. If you don’t change the old coolant on time
  5. If the fins of the radiator fan clogged with contamination
  6. Worn radiator cap
  7. A bad or failed water pump
  8. Heater hose, water pump, or engine block leak
  9. A blocked or failed engine cooling fan

What are the symptoms of a bad Engine Cooling System?

  1. Temperature gauge warning light
  2. Decreasing gas mileage
  3. A quick reduction in the coolant level
  4. Black or dark color of the coolant
  5. Engine overheating
  6. Frozen coolant
  7. Hard engine starting conditions

What are common problems of the cooling system in a car?

  • Faulty water pump
  • Damaged radiator hose
  • Coolant leaks
  • Low coolant levels
  • Faulty thermostat

How can I improve my cooling system performance?

  • Ensure regular maintenance
  • Ensure proper position of vents and fans to facilitate efficient air circulation
  • Change your cooling system’s stock fans with higher-quality fans to improve airflow
  • Shroud the fan
  • Check the radiator cap and replace it if needed
  • Use the proper thermostat
  • Clean your radiator to remove contaminants

What happens if air is trapped in radiator?

Air trapped inside the radiator can mix with water and metal, causing rust to form. This rusting can harm the radiator and make it wear out faster. It’s important to remove trapped air to prevent this damage.

Read More
  1. Types of Engines
  2. Types and Working of IC Engine
  3. Different types of Cooling Systems
  4. Signs of a bad Car Heater
  5. How to Put Water in Car Radiator 

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