Virtually, the vast majority of road-going vehicles and all late model cars are equipped with radiator fans that help to maintain optimum operating temperature.
They’re located close to the radiator to help cool the engine and radiator by pulling air through the radiator fins, especially during low speed or idle, where there is little or no air to pass through the radiator fins.
The cooling fan helps the radiator maintain the right operating temperature by providing airflow to the engine and radiator.
Cooling fans have similar electric motors to regular industrial use electric motors. The radiator cooling fans are often replaceable and serviceable components of the cooling system, making them easy to replace when they fail.
When the radiator fan spins, it generates air. Suppose they eventually fail; they will affect other engine components. To prevent engine overheating, you should be on the lookout for Symptoms of a Bad Radiator Fan and know how to check if the radiator is working.
What is a Radiator Fan?
The radiator fan is a cooling system fan that blows cold air through the radiator to lower the temperature of the coolant and cool the car engine.
The radiator fan is located between the engine and the radiator. It is especially helpful when the vehicle is stationary or running very slowly to pump air to the grill.
The main function of the cooling fan is to extract the coolant heat and prevents the engine from overheating. Therefore, the efficient working of the fan is very important to prevent the engine from overheating and other damage.
This fan blows air via the radiator to lower the engine temperature. It is often employed at low speeds and will idle when air cannot flow naturally by the system.
If the air that cools the radiator does not flow through the radiator, the engine will start to overheat.
Engine overheating is one of the most common symptoms of a bad cooling fan. Also, the air conditioning performance may be poor than usual, or you may hear a growling noise coming from the engine compartment.
What’s The Function Of A Radiator Fan?
Every vehicle comes equipped with a radiator fan, while some use two for maximum performance. These cooling fans are designed to remove the heat from the coolant that’s circulating through the motor.
These fans are also needed to cool down the air conditioning refrigerant, so you get cold AC in the middle of summer. Some people refer to the fan as a condenser fan or the cooling system fan.
Depending on what type of vehicle you drive, there are various kinds of cooling fans. Your car has one of these two options.
- Mechanical: Most older vehicles use a mechanical radiator fan. It’s also found on some rear-wheel drive cars and many of today’s trucks. The mechanical fans contain a built-in clutch allowing the fan to idle if the engine is cold enough. It activates the fan when the coolant temperatures start to climb.
- Electric: Modern vehicles rely on this design, with a fan driven by an electric motor. The ECU determines when the fan should turn on and off.
With either system, as you drive, air moves through the grille to flow over the condenser and through the radiator. The cooler air is going to remove some heat from the coolant and the air conditioning system naturally.
Yet, when you stop driving or you aren’t going fast enough to keep the flow up, things are going to start heating up without the right airflow. That’s where the cooling fans jump into action.
The fans kick on to create airflow for the condenser and radiator. It creates enough cool air to remove the heat from the refrigerant and coolant.
It can also activate while driving at higher speeds if more airflow is needed, especially when the engine is working hard, such as when you are towing a heavy load and have the air conditioner running.
Radiator Fan Location
The mechanical fan is found mounted to the water pump pulley near the front of the engine.
With an electric cooling fan, you will look for the plastic fan blades right behind the radiator. All vehicles today have a cooling fan, while the style of the two may be slightly different.
Depending on what kind of vehicle you drive, you may see two cooling fans on the radiator. This design ensures that there’s some cooling occurring if one of the fans fails.
What are the signs and symptoms of a bad radiator fan?
Just like every other issue that occurs in a vehicle, there are a few symptoms that indicate a lousy radiator cooling fan. Hence, if you notice any of these symptoms, you have to inspect or call for professional assistance to thoroughly inspect your radiator fan.
#1. fan not coming on.
The most common bad cooling fan relay symptom is that the cooling fan will not come on. If the electric motor fails or burns out, which is usually the case, the fan will not work.
This is because the electric fan motor works together in harmony with the fan blades to pull air through the radiator fins.
#2. Blown radiator fan fuse.
A blown radiator circuit fuse is another symptom of a failing or lousy radiator fan. If the electric motor surges or fails, it will blow the cooling fan circuit fuse to keep the rest of the system safe from any electrical surge. The blown fuse will have to be changed for the radiator fan to start working.
#3. Temperature warning light.
The temperature warning light indicates a problem in the cooling system. Whether or not you’re driving and this pops up on your dashboard, you have to shut off the car and allow it to cool to prevent overheating.
Chances are, the temperature warning light pops up because you have a failing or lousy radiator fan.
#4. Poor A/C performance.
If you notice the radiator fan not working when AC is on, you should seek professional advice. A lousy radiator fan can create car air-conditioning (AC) issues. This is because the radiator cooling fan creates double the amount of air that the condenser fan.
The radiator fan pulls air through the condenser, which removes the heat vapor of the refrigerant inside. If the radiator fan fails, it will affect the AC performance.
#5. Vehicle Overheating.
Engine overheating, a typical bad radiator symptom, occurs whenever there is a problem with the cooling system. Electric radiator fans are designed to come on once certain conditions are met or a specific temperature is reached.
If the radiator fan fails, the engine temperature will continue to rise until the engine overheat.
Since engine overheating is a common problem with the cooling system and can be caused by various problems, you have to diagnose or contact a professional mechanic to track down the cause of the overheating.
#6. A loud whirring Noise.
In some cases, when the radiator cooling fan motor fails, you’ll notice a loud clicking or whirring noise that changes as you rev your engine.
The radiator cooling fan is sensitive and works together in harmony with the blades, and if one of them goes out of place, it might come in contact with other components and vibrates.
When the fan clutch begins to fail, it will cause an embarrassing whirring noise. Bad radiator fan noise might be so loud, but fixing it on time will save you from the expensive repair costs.
Cause of A Bad Radiator Fan
A radiator fan goes bad due to one or more of the following causes:
- Blown Radiator Fan Fuse
- Faulty Fan Relay
- Insufficient Coolant
- Physical Damage
- Bad Coolant Temperature Sensor
- Broken Wiring
#1. Blown Radiator Fan Fuse.
Maximum parts of electric vehicles use circuit fuses. Similarly, the cooling fan also has a fuse. As the fuse blows, the fan motor stops working. In case of a blown or burned fuse, the fan couldn’t receive power from the system.
The fan motor failure or power surge can also blow the fuse and prevent damage to other components. In case of a blown fuse, you must replace it immediately for the efficient working of the fan.
#2. Faulty Fan Relay.
The radiator fan often requires a significant amount of current, and thus, there’s a relay that supplies power to it. This relay can be damaged, preventing the radiator fan from operating.
The fan relay is typically positioned in the engine compartment’s fuse box. However, it’s always a good idea to refer to your manufacturer’s manual to determine its exact location.
#3. Insufficient Coolant.
If your vehicle has insufficient coolant, it could potentially push air into the cooling system, leading the coolant temperature sensor to misread the actual coolant temperature. In such a situation, it’s crucial to refill the coolant tank.
A low coolant level may lead to engine overheating and, in a worst-case scenario, may also cause the engine to seize.
Overheating due to coolant loss can badly damage your engine, resulting in significant repair costs. Therefore, you should always maintain sufficient coolant levels in your vehicle.
#4. Physical Damage.
If your radiator fan isn’t functioning, it could indeed be attributed to defective radiator fans. Your fan may be damaged by an accident or harsh conditions. The electric motors within these fans can degrade over time and eventually fail.
To test the electric radiator fan quickly and easily, you can follow these steps:
- Get a wire from the car battery.
- Disconnect the fan connector.
- Then, put a protected 12v+ wire (a wire with a fuse) and a ground wire into the connector.
#5. Bad Coolant Temperature Sensor.
Car models generally use one of two systems: either the fan control is integrated with the motor control unit, or there’s a separate fan control module.
In both scenarios, these control mechanisms rely on a temperature sensor to determine when to engage the cooling fans.
Your vehicle’s radiator fan won’t operate efficiently when the coolant temperature sensor goes bad. Few vehicles have distinct engine coolant temperature sensors for the engine control module (ECM) and the radiator fan.
#6. Broken Wiring.
If your engine is overheating and the radiator fan isn’t activating, the issue may stem from faulty wiring or a poor connection. Inspect the wires that connect the relay or controller to the radiator fan. Look for any signs of corrosion on the connectors.
Testing wires with a multimeter isn’t always the best way to check if they’re working because you really need to put them under stress to know for sure. But you may use a multimeter as a first step to see if electricity is getting to the radiator fan.
Diagnostic Steps
Since a nonfunctioning fan can lead to engine failure, it’s super important to address the issue immediately; ignoring it has some very spendy consequences. Here’s how to troubleshoot and identify potential problems with your radiator fan:
- Inspect Fan Blades: Turn off the engine and visually inspect the radiator fan blades for any signs of obstructions, as well as check for damage, such as cracks, chips, or missing pieces. Damaged blades can affect the fan’s efficiency and airflow, leading to overheating.
- Scan for Diagnostic Trouble Codes (DTCs): Use an OBD-II scanner to retrieve any stored codes related to the cooling system or radiator fan operation. DTCs can provide valuable insights into specific issues affecting the fan’s performance.
- Check Fan Operation: Start your vehicle and let it idle until it reaches operating temperature. Observe whether the radiator fan kicks in as the engine heats up. If the fan doesn’t activate, it may indicate a problem with the fan motor, relay, fuse, or temperature sensor.
- Verify Coolant Levels: Low coolant levels can affect the radiator fan’s ability to cool the engine effectively. Check the coolant reservoir and radiator for proper fluid levels and signs of leaks.
- Fan Wiring & Connector: Visually check the fan wiring, mice love to eat wiring, especially if your vehicle has been sitting up for a while. Check the connector is secure and corrosion-free.
- Test Fan Power Supply: Use a multimeter to check the power supply to the radiator fan (both fuse and relay are typically housed in the engine compartment fuse box). Ensure that the fan is receiving the correct voltage when it should be operating. This step helps determine if the issue lies with the fan motor, wiring, or electrical components.
Checking the Cooling System
With so many components working together, you can’t just go right to the radiator, unless you already know it’s the problem. At the dealerships, we like to work through a series of checks to find the failed parts.
Check 1: Failed thermostat.
You will need an infrared temperature gun. Then, follow these simple steps:
- Warm up your car engine. Give it ample time.
- Look for the radiator hoses. There is an upper and lower radiator hose on your car.
- Scan the radiator hose temperatures with the infrared gun. Wait for your engine to overheat and measure both hoses.
- If both hoses stay cold, or just one becomes hot, then you have a bad thermostat. Don’t be a macho man and attempt to measure this by touching the hoses. Obviously, they can get very hot and you could burn your hand.
Check 2: Clogged radiator.
If your radiator has an internal clog, the coolant flow is restricted. If you have an external clog, it might cause the airflow to become restricted and lead to overheating. Here’s what you need to do to check:
- Your engine must be cool. Leave it parked and off until it’s not warm at all.
- Look inside the radiator. You need to remove the cap and inspect for debris. If you have an internal clog, you’ll need to replace the radiator.
- Look for external clogs. Examine the front of your radiator for debris that could have clogged it. You should be able to clean an external clog with a garden hose or compressed air.
Check 3: Cooling system leak.
If there’s a leak in the cooling system, your engine will overheat. You must repair this immediately if you want to prevent further damage. To perform this check, you’ll need a cooling system pressure tester and coolant dye kit.
- Cool the engine completely.
- Take off the pressure cap and set it somewhere safe.
- Follow the manufacturer’s instructions and apply pressure with your tester. Don’t exceed what’s written on your radiator cap.
- Examine the system for a leak.
- If you need to, add some coolant dye after removing your tester.
- Put your radiator cap back on and start your engine.
- Watch for a leak by keeping an eye open for the dye. Sometimes, it takes days of regular driving until you see the dye—this indicates a slow leak.
Check 4: Defective cooling system pressure cap.
Can a bad radiator cap cause overheating? Yes. If your cap isn’t holding pressure, the coolant starts to boil and leads to an overheating engine. Keep your system pressure tester handy for this check as well.
- Cool the engine completely.
- Unscrew the pressure cap and remove it.
- Use your pressure tester on the cap. Make sure it holds the recommended amount, as per the cap. If not, replace it.
Check 5: Malfunctioning water pump.
When a water pump breaks, it doesn’t circulate the right amount of coolant. This also leads to an overheating engine. You don’t want to check this until you’ve done the thermostat inspection first.
- Cool the engine completely.
- Take off the pressure cap.
- Start the engine and watch the coolant to see if it begins circulating.
- If it doesn’t move, you could need a water pump.
- Look at the water pump. It might have signs of a leak. Look for wet spots or dry green or white residue.
Check 6: Faulty radiator cooling fan.
When the cooling fan fails, your engine overheats.
- Park the car.
- Look for the cooling fan. It might be mechanical or electric, but the engine drives it.
- Start the car and let the engine warm up.
- When the engine temperature rises higher than normal, inspect the cooling fan. If it doesn’t turn on or seems to be running slow, this might be your problem. For a mechanical fan, you must replace the clutch. With an electric fan, you want to diagnose the circuit first.
Check 7: Defective head gasket.
The issue no one wants to have is an internal problem with the engine, but it happens often. The way to prevent this is to repair cooling system defects immediately. That means, don’t put water in your radiator and ignore the leaks.
To perform this check, you’ll need a block test kit.
- Cool the engine.
- Remove the radiator cap.
- Hook up your block tester. Make sure you follow manufacturer specs.
- Watch for an indication of combustion gases in your cooling system. If it shows evidence of gases, you have to disassemble the engine for further troubleshooting.
As you can see, finding out if you have a bad radiator is more complicated than just looking at the part.
That’s because the cooling system contains multiple components, and when one aspect isn’t running right, it leads to the same symptoms. You can’t automatically tell that a thermostat or radiator is the culprit just because the engine overheats.
Replacing the Radiator Fan
If diagnostic tests confirm that your radiator fan needs replacement, here’s a step-by-step guide on how to proceed:
- Gather Materials: Before starting, gather the necessary tools and parts, including a new radiator fan assembly, socket set, screwdrivers, and possibly a trim removal tool.
- Prepare the Vehicle: Ensure the engine is cool. Place the vehicle on a flat surface and engage the parking brake for safety.
- Access the Radiator Fan: Depending on your vehicle, you may need to remove the radiator grille, front bumper, or other components to access the radiator fan assembly. Refer to your vehicle’s service manual for specific instructions.
- Disconnect Electrical Connections: Locate and disconnect the electrical connectors leading to the radiator fan. Be cautious and avoid damaging the connectors or wiring harness.
- Remove Mounting Hardware: Use the appropriate tools to remove the mounting bolts or screws securing the radiator fan assembly to the vehicle. Keep track of each fastener and any associated clips.
- Install the New Radiator Fan: Position the new radiator fan assembly in place and secure it with the mounting bolts or screws. Reconnect the electrical connectors to ensure proper operation.
- Reassemble Components: If you removed additional parts to access the radiator fan, reinstall them carefully. Double-check all connections and fittings.
- Clear Fault Codes (if applicable): Use an OBD-II scanner to clear any fault codes related to the previous radiator fan issues.
- Test the New Radiator Fan: Turn on the AC to verify that the new radiator fan operates correctly. Monitor the temperature gauge to ensure proper cooling.
- Final Checks: Once confirmed operational, close the hood and take the vehicle for a short drive to ensure everything functions correctly.
How Much Does It Cost To Replace A Radiator Fan?
You may spend between $500 and $750 to replace a radiator fan. The fan alone will cost between $350 and $500, with the labor adding the other $150 to $250. However, some vehicles can cost more, depending on the make and model, as well as the local labor rates.
With the radiator fan mounted to the radiator, you may feel equipped to change it yourself. With some basic tools and generalized mechanical knowledge, this job shouldn’t be too complicated for you.
Give yourself a few hours for the repair and you may save money on the labor costs. Keep in mind that you shouldn’t drive your car if the radiator fan has failed.
Without the proper airflow on the radiator, your engine could quickly overheat. Continuing to drive a car with an overheating engine is a surefire way to send your vehicle to the junkyard because of a blown motor.
FAQs.
Q: What happens when a radiator fan stops working?
What happens when a radiator fan stops working? It will cause a loud whirring noise and a stuck open thermostat (which will not allow the engine to reach the average operating temperature).
A lousy radiator cooling fan could cause a blown circuit fuse, a malfunctioning relay, and engine overheating.
Q: Can you drive with a bad radiator fan?
Yes, if your radiator cooling fan fails, you can drive with it. Technically, your vehicle engine does not need a radiator fan to operate.
However, if your vehicle engine does not receive enough air blowing it constantly, it will eventually lead to overheating. So, you don’t have to drive a long distance with a lousy radiator fan to avoid overheating.
Q: What does a bad radiator fan sound like?
Every car has a kind of noise they make. After driving your vehicle for a long, you should know how your vehicle sounds and be able to detect when something is out of place.
In some cases, when your radiator cooling fan clutch fails, it will develop a whirring or clicking noise. The noise could result from a bearing that is out of place or a bent fan blade that is touching other components.
Q: When should a radiator fan come on?
Mechanical radiator cooling fans will come on immediately after you start your engine. On the flip side, the electric radiator cooling fan will only turn on when the car engine reaches a certain temperature.
However, if your car is equipped with an electric radiator cooling fan, it should come on at about 200 degrees Fahrenheit. If you notice your engine is running hot or overheating, you have to check if your radiator fan is blowing.
Final Words
As the radiator cooling fan is a vital component of the cooling system, it is essential in maintaining the engine’s optimum operating temperature. When it starts failing or eventually goes bad, the car engine will start overheating.
If you notice your engine is showcasing any of the symptoms of the bad radiator fan above, ensure you contact a professional mechanic to inspect and fix the problem.