How to Check Your Car's Cooling System Quickly and Easily

Car cooling system plays a key role in maintaining the optimum operating temperature of the engine, preventing overheating and ensuring stable performance. Without a cooling system, engine temperatures can skyrocket to levels that cause serious damage, reducing the life and performance of the vehicle.

According to statistics from leading car manufacturers, about 40% of serious engine failures are caused by cooling system problems. The cost of repairing an engine due to overheating can be up to tens of millions of VND, while regular maintenance of the cooling system only costs from 500.000 VND to 2 million VND. 

This article will help you better understand how the cooling system works, warning signs of a problem, testing procedures, troubleshooting, and important notes. Don't miss it!

Understand the operating principles of the car cooling system

The car's cooling system is an important part that helps maintain engine temperature within a safe range (from 80°C to 95°C), preventing overheating and prolonging the life of the vehicle. 

This system works through the coordination of many main components such as radiator, water pump, thermostat, cooling fan and pipes. Coolant is circulated to transfer heat from the engine to the environment. 

There are two common types of cooling systems: air-cooled and liquid-cooled, with liquid cooling being more commonly used in modern cars.

1. The role of the cooling system for the engine

The cooling system acts as an engine thermostat, keeping the engine operating at an optimal temperature, typically between 80°C and 95°C. 

An internal combustion engine generates a large amount of heat when operating; the cooling system releases this excess heat into the surrounding environment, preventing overheating that can damage machine parts such as pistons, cylinders, and cylinder head gaskets.

2. Main parts and relationships

The cooling system consists of many components that work together to dissipate heat, including the radiator, water pump, cooling fan, thermostat, and pipes.

3. Common types of cooling systems

There are two common types of cooling systems in cars:

• Air-cooled system: This system uses air directly to cool the engine. Cooling fins are arranged on the engine body and cover to increase the contact area with air. This type is often found on old motorbikes or some classic cars.
• Liquid-cooled system: This system uses coolant to transport heat from the engine to the radiator. This is the most common type of system on modern cars.

What are the signs that your cooling system is having problems?

A problem with your cooling system can be signaled by visual and audible signs, coolant-related signs, or engine performance signs. Recognizing and responding to these signs can help you avoid serious and costly engine damage.

1. Visual and audio cues

Visual and audible signs may include a temperature warning light on the dashboard, steam coming from the hood, or strange noises coming from the engine area.

• Temperature gauge reading high or overheating warning light: This is the most obvious sign that the engine is overheating. For example, the gauge needle points to the red zone or the thermometer warning light illuminates.
• There are strange noises coming from the engine area: A rattling noise can be caused by a broken water pump, a squealing noise can be caused by a loose or broken belt, and a boiling noise can be caused by boiling coolant.
• Steam coming from the hood: This is a serious sign that the coolant is boiling due to overheating.

2. Signs related to coolant

Signs of coolant problems may include rapidly dropping coolant levels, leaking coolant, or coolant that is unusual in color.

• The coolant level in the expansion tank is unusually low: This could be due to a leak somewhere in the system.
• Discolored Coolant: Coolant that is cloudy, contains dirt, rust, or oil is a sign of a problem with the cooling system.
• Coolant leak under the vehicle: Check the pipes, radiator, and water pump for leaks.

3. Engine performance signs

Signs related to engine performance may include engine misfiring, reduced power, or increased fuel consumption.

• Weak, sluggish, difficult to start engine: Overheating can reduce engine performance.
• The car consumes more fuel than usual: The engine has to work harder when it is overheated.
• The exhaust is white, especially in the early morning.

What are the steps in checking car coolant?

The basic inspection procedure includes checking the radiator, water pump, cooling fan, thermostat, and coolant hoses. Here are step-by-step instructions for you to perform at home.

1. Check the radiator

Checking the radiator includes checking the coolant level, leaks, and condition of the radiator cap. The main steps to checking the radiator include:

Step 1: Make sure the engine is completely cool.

Step 2: Open the hood and locate the radiator.

Step 3: Check coolant level:

• In the sub-tank: The water level must be between the “MIN” and “MAX” lines. If lower than “MIN”, add more coolant.
• In the radiator (if fitted): Open the radiator cap (only when the engine is cold) and check if the water is full. If not, add more.

Check coolant quality:

• Color: Coolant should be clear, free of dirt, rust or oil. If the water is cloudy or has an unusual color, drain and replace it.
• Concentration: Use a coolant tester to check. The concentration must be as recommended by the manufacturer (usually 50/50 or 60/40 between distilled water and antifreeze).

Step 4: Check the radiator cap – Make sure the cap is tight, not cracked or broken, and the rubber gasket is in good condition. The radiator cap maintains pressure in the system.

Step 5: Check the overall water tank – Observe the water tank for signs of dents, leaks, or blockages.

2. Check water pump and cooling fan

Checking the water pump and cooling fan includes checking for noise, vibration, and operating condition of the components.

Check water pump:

• Observation: Check for coolant leaks around the water pump.
• Listen: When the engine is running, listen for any strange noises (rattling, screeching) coming from the water pump.
• Check Belt: Make sure the water pump drive belt is not loose, cracked or slipping.

Check cooling fan

• For electric fans: Turn on the air conditioning (A/C) and check if the fan is spinning. If the fan is not spinning, check the fuse, relay, and fan motor.
• For centrifugal fans: When the motor is cool, try turning the fan blades by hand. The blades should turn smoothly but with some squeaking. If the fan turns too easily or too hard, the viscous coupling may be damaged.
• When the engine is hot: Observe whether the fan spins more vigorously as the engine temperature increases.

3. Check the thermostat and coolant pipes

Thermostat and coolant hose inspection includes checking the hose temperature and the condition of the thermostat.

Check thermostat:

• Method 1 (difficult to do at home): Remove the thermostat and dip it in hot water. Observe whether the valve opens at the specified temperature (usually printed on the valve body).
• Method 2 (easier): When the engine is cold, feel the hose that carries water from the engine to the radiator. It should be cool. Once the engine has warmed up (the temperature gauge needle is near the middle), feel the hose again. It should heat up quickly, indicating that the thermostat has opened.

Check water pipes:

• Observation: Inspect all piping for cracks, bulges, leaks or blockages.
• Feel: When the engine is cool, squeeze the hoses. The hoses should be flexible, not stiff or brittle.

4. Use specialized equipment to check the cooling system

If you want a more thorough check, you can use specialized equipment:

• Cooling system pressure tester: Helps detect leaks in the system.
• Coolant tester: Indicates the exact ratio of water and antifreeze.
• Borescope: Helps check inside water tanks and pipes for blockages or corrosion.
• Infrared thermometer: Helps measure the temperature of different parts in the cooling system, detect unusual hot spots.

How to troubleshoot common cooling system problems?

Here's how to fix common problems like an overheating engine, coolant leaks, or faulty components like the thermostat, water pump, or cooling fan.

1. Engine Overheating Treatment

Engine overheating is a serious problem that can cause significant damage to your vehicle. When the engine overheats, the following actions should be taken:

• Pull over safely and turn off the engine: Do not attempt to drive with an overheated engine.
• Open the hood (carefully): Use a thick towel to cover your hands when opening the hood to avoid burns from hot steam.
• Wait for the engine to cool completely: Never open the radiator cap while the engine is still hot.
• Check coolant level: If low, add coolant (or temporarily distilled water).
• Check other parts: See if there are any leaks, if the fan is spinning, if the belt is broken.
• If you cannot fix it yourself, call for help.

2. Fix coolant leaks

Coolant leaks are a common problem in cars that can cause serious consequences if not handled promptly. To fix a coolant leak, you need to:

• Locate the leak: Check the tank, pipes, water pump, and joints.
• Small leaks: Radiator sealant can be used to temporarily seal the leak. However, this is only a temporary solution and you should repair or replace the damaged part as soon as possible.
• Large leak: Replace damaged parts (pipes, radiator, water pump…).

3. Replace coolant

Regularly replacing the coolant (usually every 40.000 – 60.000 km or 2-3 years) helps maintain cooling efficiency and prevent corrosion. 

• Drain all old coolant from the system. 
• Clean the system with clean water or specialized cleaning solution. 
• Add new coolant to the system at the manufacturer's recommended ratio (usually 50% water and 50% ethylene glycol). 
• Bleed air from the system to ensure good coolant circulation.

4. Replace thermostat, water pump, cooling fan

When the thermostat, water pump, or cooling fan fails, they must be replaced to ensure proper cooling system operation. Remove the old parts and install the new parts according to the manufacturer's instructions. Make sure the parts are properly seated and the screws are tightened.

What to note when checking & repairing the cooling system effectively?

Working with hot engines, handling used coolant, using protective gear, and being mindful of system pressure are important factors to consider.

1. Working with hot engines

Always wait for the engine to cool completely before inspecting or servicing the cooling system. A hot engine can cause serious burns. If it is necessary to work on a warm engine, use protective gloves and take care to avoid contact with hot parts.

2. Used coolant treatment

Used coolant contains toxic chemicals and needs to be disposed of properly. 

• Do not discharge coolant down the drain or into the environment. 
• Collect used coolant in a sealed container and take it to a recycling or hazardous waste disposal center. 

Ethylene glycol in coolant can be harmful to health if swallowed or comes into contact with skin.

3. Use protective equipment

Use gloves, goggles, and protective clothing when inspecting and repairing the cooling system. 

• Gloves help protect skin from contact with chemicals and hot parts. 
• Safety glasses help protect eyes from dust and splashing liquids. 
• Protective clothing helps protect the body from stains and scratches. 

4. Note on system pressure

The cooling system operates under pressure, so care must be taken when opening the radiator cap or removing system components. 

• Open the radiator cap slowly to gradually reduce the pressure.
• Do not remove pipes or components while the system is pressurized.

5. Fire and explosion prevention

Coolant contains flammable substances, so keep away from fire and heat sources when working with the cooling system. 

• Do not smoke or use open flames near work area. 
• Ensure work area is well ventilated to avoid accumulation of flammable vapors.

FAQ – Frequently Asked Questions

1. Can tap water be used instead of specialized coolant?

Do not use tap water instead. cooling water Specialized coolant, as tap water contains minerals that can cause corrosion and scale buildup in the cooling system. Specialized coolant contains additives that help protect the system from corrosion, scale buildup, and freezing. See products now: Castrol Engine Coolant – Radicool SF Premix – Red 500 ml.

2. How do I know if the coolant has expired?

Expired coolant often has an unusual color (e.g., rusty brown or milky), or contains sediment. You can also use a coolant tester to measure the concentration of ethylene glycol and determine whether the coolant is still protecting the system.

3. What are the signs that the cooling fan is not working effectively?

Signs that the cooling fan is not working properly include the engine overheating when the vehicle is moving slowly or at a standstill, strange noises coming from the fan, or the fan not spinning when the engine is hot.

4. What types of additives can support and protect the car's cooling system?

There are many types of additives that can support and protect Car cooling system, include:

• Anti-corrosion agent.
• Antiscalant.
• Antifreeze.
• Water pump lubricant.

These additives help extend the life of the cooling system and improve cooling efficiency.

5. Can I repair my cooling system at home?

Repairing the cooling system yourself at home can be done for simple tasks such as changing the coolant or replacing the pipes. However, for more complicated tasks such as replacing the water pump or thermostat, you should take your car to a professional garage to ensure safety and quality. Check out the quick and simple ways to check the cooling system yourself at the link: https://thanhphongauto.com/kiem-tra-he-thong-lam-mat/.

6. Which garage repairs/maintains cooling systems with good reputation and good price in HCM?

Thanh Phong Auto is one of the leading prestigious garages in Ho Chi Minh City, specializing in providing repair and maintenance services for car cooling systems with superior quality. Below are the outstanding advantages of the service here:

• Experienced team of technicians: Thanh Phong Auto has a team of professional technicians, well-trained to handle all problems related to the cooling system, from radiators, water pumps to cooling fans and thermostats.
• Modern equipment: The facility is fully equipped with specialized equipment, ensuring that repair and maintenance processes are performed quickly and accurately.
• Genuine spare parts: All replacement parts are genuine, ensuring high quality and reliability.
• Prestigious warranty policy: Thanh Phong Auto provides long-term warranty policy for repair and maintenance services, helping customers feel secure when using the service.
• Competitive price: Service prices at Thanh Phong Auto are always competitive compared to other units in the market, bringing customer satisfaction in both quality and cost.
• Diverse services: Not only repairing and maintaining cooling systems, Thanh Phong Auto also provides many other services such as 24/7 rescue, periodic maintenance, and replacement parts.

With the above advantages, Thanh Phong Auto is the ideal destination for any car owner who wants to ensure the vehicle's cooling system operates effectively and prolongs the life of the engine.