Car Vibrate When Radiator Fan Turns On

Why Does My Car Vibrate When Radiator Fan Turns On? Causes and Prevention Measures  

Vibrations when the car radiator runs are somewhat common in some circumstances. However, it also adds an electrical load on the engine and makes it run hard. But should this cause the car to vibrate?

So, why does my car vibrate when radiator fan turns on? Most times, imbalanced fan blades or a faulty fan can cause vibration. The alternator might also be the cause or the accessory bracket due to the increased load on the belt.

The article provides the possible causes why a vehicle may vibrate when the radiator fan turns on. Read on to learn the causes, solutions, and how to avoid future problems.

What Causes Car to Vibrate When Radiator Fans Turn On?

Like most problems, the vibration issue has various causes. Following are the possible causes of the vibration when the radiator is active and their solutions.

What Causes Car to Vibrate When Radiator Fans Turn On

1. Imbalanced Fan Blades

Since the fan controls airflow when AC is on, it’s usually the first suspect. One of the possible issues might be an imbalance on the fan blades.

Due to rough driving or a minor accident on the front bumper, the fan may shift. This can cause the fans to hit against its casing when they become active, causing the vibration.

Imbalanced Fan Blades


While replacing the fan might seem like the ultimate fix, you can try repositioning it. Thus, repositioning the forward-facing air intake and the attached wiring can solve this issue.

2. Faulty Fan

A fault in the fan itself can also be the main cause of the vibration. If one of the blades is damaged, they may be grinding on the plastic covering, causing vibration. A faulty fan is the most common cause in most reports.

Also, a worn-out fan clutch can make rattling noises, and if paired with other problems, it can cause vibration.

Faulty Fan


The best choice for a faulty fan is to replace it with a new set. You may try to repair the old one, but if the causes are more than one, it might be costlier.

3. Faulty Alternator

If the alternator starts failing, it is unable to provide the required amount of power. Thus, the alternator might be having power interruptions or be too weak to work. When power is in demand by features like the air conditioner, the alternator may shake, causing vibration.

Faulty Alternator


You can either repair or replace the alternator with a new one. An alternator costs between $100 and $450 to replace, with repair costs included.

4. Worn Out Mounts

The engine itself might be the cause of the vibration. If the accessory bracket to the engine block mounting bolt wears out, it might allow vibration. And the engine may vibrate due to increased belt load when the radiator fans become active. 

What Causes Car to Vibrate When Radiator Fans Turn On


If the mounts cause vibration, change the accessory bracket with a new one.

Diagnosing The Car Vibrating When the Radiator Fan Turns on 

Diagnosing The Car Vibrating When the Radiator Fan Turns on

While taking your car to a mechanic for diagnosis may seem like the better choice, you can also diagnose it. With a little experience with vehicles and plenty of time, you can figure out the cause by checking the following things.

  • Jump start the fans with your vehicle’s battery when the engine is off to test them for any vibration. If none, you can rule out the fan as the cause.
  • Disassemble the fans and observe for any damage on them that might be causing them to wobble. You might be able to hear the rattling noises from nearby.
  • You can disconnect the alternator for some time and observe for any shaking during that time. However, the battery should be full enough to power the fan or air conditioning. If there is no shaking, the alternator is the cause.
Diagnosing The Car Vibrating When the Radiator Fan Turns on

How To Prevent Car Vibrating When Radiator Fan is on?

Like any other car problem, diagnosing and repairing is expensive in both time and money. Therefore, avoid the problem in every way possible. The following tips will help you prevent the vibrating issue.

How To Prevent Car Vibrating When Radiator Fan is on

1. Service The Radiator

Regular servicing of the car’s radiator may help prevent problems. You may also be able to spot a fan problem on time and fix it, preventing future damage.

2. Service the battery

Service and keep the car battery on top performance to prevent alternator problems. The battery status directly affects the alternator, and if the battery is healthy, the alternator is healthy.

3. Avoid damage to the Radiator

Avoid damage or hard-hitting the radiator area. During servicing, let the professionals handle it to avoid misalignment and damages.

Avoid damage to the Radiator

4. Change engine mounts on time

Engine mounts are rubber made, which wear with time. Regularly check for loose motor mounts, and replace them on time. 

Car vibrating when the radiator fan turns on can be a frustrating and potentially dangerous problem. At MotorAdvices, we have articles that address a range of issues related to car vibrations, including what to do when you notice white or blue powder on your car battery and when your car hesitates and jerks when accelerating. Our article on car battery with white or blue powder discusses the causes of the white or blue powder on your car battery and provides tips on how to clean it. Additionally, our article on car hesitating and jerking when accelerating explains the possible reasons for this issue and offers solutions to help you keep your car running smoothly. Visit MotorAdvices to learn more about how to keep your car running smoothly and address any vibrations or issues you may be experiencing.


The following are frequently asked questions related to the car vibrating when the radiator fan is active.

Q: Is it safe to drive when the car is vibrating?

No. It’s highly discouraged to drive when your vehicle vibrates when radiator fans are active. However, you can drive to a service station to get help while preventing the radiator fans from becoming active.

Q: What Is the cost of fixing a vibrating car when the radiator fan is on?

The cost of repairing a vibrating car when the Ac is on depends on the cause. A fan repair can cost between $100 and $300, while engine mounts cost between $10 and $200.

Q: Is it a sign of a faulty radiator when the car vibrates after the radiator fans are on?

The vibration has many causes, but the radiator can also be one of them. Diagnose each part one after the other to determine the cause of the vibration issue. 

Bottom Line

While vehicles are known to vibrate when active, too much vibration can signify a failing part. With the above problem only present when radiator fans become active, the causes must be related. To determine the cause, you can perform the diagnosis.

A faulty fan is one of the reasons why a car vibrates when radiator fan turns on. The solution involves repairing or replacing the failing part. Also, the tips should help you prevent future vibration problems when the radiator fan is active.

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