Bad Fan Clutch Symptoms

Reviewed by

Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on December 19th, 2024

Reading Time: 6 minutes
Summary
  • The fan clutch is the component that engages and disengages the cooling fan, increasing airflow over the radiator and engine.
  • You can tell if a fan clutch is faulty if the engine overheats and malfunctions or if the cooling fan is too noisy.
  • Replacing a fan clutch costs anywhere between $30 and $530. Prices will vary depending on your specific vehicle as well as labor costs in your area.

What Is the Fan Clutch?

One of the engine cooling system’s indispensable parts is the fan clutch. It engages and disengages the cooling fan, which increases airflow over the radiator and engine. If the fan clutch develops a problem, it will hamper the engine’s operation. By familiarizing yourself with bad fan clutch symptoms, you can more easily identify an issue early and take action to nip it in the bud.

How To Tell if the Fan Clutch Is Bad

The fan clutch consists of several components that can wear out over time. That being said, the fan clutch usually lasts the life of the vehicle, so you may never see any problems at all.

The fan clutch engages and disengages the cooling fan, which increases airflow over the radiator and engine.

Listed below are the fan clutch symptoms that commonly show up if the clutch wears out or fails:

Check Engine Light Switches On

If the powertrain control module (PCM) detects an engine issue, it will activate the check engine light. A bad fan clutch can cause engine problems like excessively high temperatures and poor performance. These issues will draw the PCM’s attention, and it will turn on the check engine light to warn you about them.

For vehicles that use an electronic fan clutch, the PCM controls the clutch and regularly checks it for issues. The computer will turn on the check engine light if it comes across something recorded in its memory, such as the one that causes it to log the P0526 code.

Engine Overheats

An overheated engine is one of the most common faulty fan clutch symptoms. When the engine burns fuel, it generates heat that builds up over time. There are several components that help reduce the engine’s temperature, one of which is the cooling fan that takes cooler air from outside the vehicle and forces it to flow over the radiator and engine.

The engine cooling fan can spin independently but relies on the fan clutch to hit the higher speeds needed to produce strong airflow. Once the clutch detects the engine temperature has reached a certain level, it will engage the fan to spin faster.

If a fan clutch wears out from heavy use or after a long time, it will reduce the cooling fan’s performance or cause the fan to operate incorrectly. In some cases, the clutch won’t activate the fan at all.

Without the cooling effect of the air blown by the fan, the engine will run hotter. If it gets too hot or runs at high temperatures without proper cooling for too long, it will overheat.

Cooling Fan Makes Too Much Noise

Do you hear the cooling fan spinning at full power when the engine isn’t running hot? That noise might indicate a problem with the fan clutch.

The fan clutch controls the cooling fan’s operation. It will engage the fan once the engine gets hot enough to warrant more cooling.

Furthermore, the fan clutch also sets the fan speed based on the engine’s temperature. The hotter the engine, the faster the clutch makes the fan spin. Higher fan speeds also make louder noises and put more strain on the fan blades.

A worn-out or damaged fan clutch might engage the cooling fan at the wrong time or leave the fan running long after the need for more cooling passes. The bad clutch might also put the fan on the fastest, loudest setting.

If the cooling fan puts too much strain on its blades, the fatigued blades might fracture or even fly apart.

Engine Performs Poorly

When a fan clutch wears out and starts acting erratically, it might reduce the engine’s efficiency.

In general, the benefits of improved cooling more than compensate for the power used by the cooling fan. However, the engine doesn’t always run so hot that it needs more airflow. Furthermore, the cooling fan can spin by itself using the air entering the front grille.

A bad fan clutch can keep the cooling fan engaged and running at high speeds even when it’s not supposed to operate. Because the cooling fan draws power from the engine to run at higher speeds, your vehicle will have less power available for propulsion. Your car will accelerate slowly and waste more fuel.

Here are two short videos about different kinds of fan clutch failures (Source: Richard McCuistian, ASE-certified Master Automobile Technician):

More About the Fan Clutch

Fan clutches use either mechanical or electronic means to control the engine cooling fans. Your vehicle’s year of manufacture will determine the type of fan clutch fitted to its engine cooling system. Older models usually feature a mechanical fan clutch, while newer vehicles switched to electronic fan clutches.

Mechanical fan clutches further subdivide into non-thermal and thermal models. A non-thermal fan clutch attaches to the water pump.

A replacement fan clutch can go for as low as $30 and as high as $530.

How Does the Fan Clutch Work?

Belt-driven fans used to spin at exactly the same speed as the water pump pulley because that’s what they were bolted to. Some fans were designed to have slightly flexible blades at higher speeds to reduce the load the fan put on the engine while still moving plenty of air through the radiator.

But in the late 1950s, viscous fan clutches began to appear. A viscous fan clutch enables the fan to more or less freewheel unless the air coming through the radiator and A/C condenser reaches a certain temperature. On the forward side of the viscous fan clutch, there is a bimetal spring (usually spiral) that is anchored at one end with the center engaged to a valve that leads inside the fan clutch.

As the bimetal spring changes shape (because this is what happens when a bimetal spring gets hot), it operates a valve inside the van clutch, reducing the free-wheeling effect so that the fan more closely matches the speed of the pulley to which the fan is bolted.

As the increased airflow cools the A/C condenser and the radiator, the spiral spring will return to its original position. It is typically analog in the way it operates. It modulates fan speed for maximum efficiency and minimum power loss. In the early 2000s, some of these viscous fan clutches became PCM controlled rather than using a spiral spring.

Electronic fan clutches use an electric coil to activate the cooling fan. The PCM draws data from various sensors, such as the coolant temperature sensor and oil temperature sensor. Based on those sensor readings, the computer will determine when to activate the fan clutch and how fast the cooling fan should run.

How Much Does a Replacement Fan Clutch Cost?

A new fan clutch can go for as low as $30 and as high as $530. Its price tag can change depending on various factors, such as your vehicle’s year, make, model, and submodel.

How to Get a High-Quality Fan Clutch

It’s best to replace your bad fan clutch right away to avoid issues like engine overheating, which could cause problems that require costly repairs. Luckily, getting an aftermarket fan clutch that fits your ride is quick and easy when you shop here at CarParts.com.

With our easy-to-use vehicle selector, you can view the top-notch fan clutches that are compatible with your daily driver. All our products passed strict quality control tests, so you can be sure you’re choosing from only the best replacement fan clutches on the market.

All our warehouses are strategically located across the US, so expect your order to reach you in as fast as two business days. We also have a 24/7 customer service team ready to assist you in case you have queries or need help placing your order.

Enjoy smooth and hassle-free trips by replacing your bad fan clutch as soon as you find out it’s faulty. Check out our wide selection of fan clutches here at CarParts.com.

About The Authors
Reviewed By Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Written By CarParts.com Research Team

Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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Published by
CarParts.com Research Team and Richard McCuistian, ASE Certified Master Automobile Technician
Tags: fan-clutch