Dirt Bike Radiator Fan Keeps Your Dirt Bike Cool

The dirt bike radiator fan kicks in automatically when the engine is hot and helps prevent overheating. Do you need one on your dirt bike? It depends.

A dirt bike dirt bike radiator fan effectively keeps the engine from overheating and boiling the coolant over. An electric fan behind the radiator turns on automatically at a set temperature. The fan quickly lowers the engine coolant temperature in low airflow conditions.

Have you ever noticed a white puff of steam coming out of the radiator cap, under the dirt bike, or notice a hot and smelly air around the engine? It means that your dirt bike engine is overheating and causing the coolant to boil over via the overflow hose. It might make sense to add an aftermarket dirt bike radiator fan.

Let’s take a closer look at when it makes sense to install a dirt bike radiator fan on your dirt bike.

In this article, we cover:

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Dirt bike steaming coolant despite dirt bike radiator fan in a race
Dirt bike overheating and boiling coolant over. A dirt bike radiator fan helps keep the engine cooler in low airflow conditions.

How Does a Dirt Bike Radiator Fan Cool the Engine

Modern dirt bike engines circulate water to cool down the engine temperature. For instance, the coolant is constantly circulating inside the engine block, around the piston and top end. The water pump circulates the hot coolant into the two radiators in front of the dirt bike. The radiator then is able to cool down the liquid circulating inside the thin fins, as the cooler air is passing through the radiator.

The airflow through the radiators is key for the system to perform well. When riding technical, very low-speed sections and obstacles, the airflow is minimal to none. That’s when the dirt bike radiator fan comes into play.

The slow speed, almost stop-and-go conditions tend to heat up your dirt bike motor more. This happens because typically you need more revs and more clutch slip to overcome obstacles or get unstuck. At the same time airflow is at a minimum.

The dirt bike radiator fan helps by turning on an electric fan on the inside of the right radiator to force more air through the radiator. This effectively cools down the liquid coolant circulating inside the radiator.

A radiator fan kits include at least an electric fan and installation brackets to mount the fan into the radiator. Additionally, the kits typically come with a temperature sensor, temperature display with control settings, electrical lines to connect to a power supply, and mounting brackets.

The electric fan is configured to automatically turn on at a certain temperature to keep the engine coolant temperature at an acceptable level.

How To Tell if Your Dirt Bike Is Overheating

Riding at slow speeds and on rough technical terrain can often lead to overheating the dirt bike. When the engine is constantly being pushed into higher revs and more clutch slip when overcoming obstacles or getting unstuck, the engine has to work harder without getting much airflow.

These are the typical symptoms of an overheating engine:

  • steam coming out of the radiators
  • extremely hot air around the engine
  • a smell of a burning coolant
  • loss of engine power
  • a knocking engine
  • a seized engine which will not start or run
  • coolant coming out of the overflow
  • oil leaking from the seals
  • hotter-than-normal cylinder

After you have overheated the dirt bike, you should make sure to inspect the coolant lines for leaks and either top off with fresh coolant or flush the system. Check out how to properly flush and air out dirt bike coolant here.

What Happens if Your Dirt Bike Overheats?

If the coolant level reaches high temperatures, it can cause several issues. For instance, the high temperatures cause oil and lubricants to work less efficient. This excessive heat will expand metal parts and cause more overall friction. In addition, this quickly leads to the engine coolant to start boiling.

For example, heavy steam and hissing sounds are an indication of the engine coolant boiling. After that, the vaporized coolant and heat opens the pressure sensitive radiator cap. The hot vapor overflows through the exhaust hose in the radiator cap to the ground.

Above all, at these temperature levels, you risk causing permanent damage to your motor, including seizing the motor. In other words, this means the piston is expanding into the cylinder causing it to seize up by friction.

How To Decide if You Need a Dirt Bike Radiator Fan

Have you boiled the coolant recently? This is an indication that the engine is running too hot.

We recommend flushing the cooling system after boiling over the coolant and to check for leaks or other issues. It’s a simple process, just follow our instructions on how to flush radiator coolant and air out the cooling system for optimal performance.

Installing a dirt bike radiator fan makes sense if your trail riding includes hard, difficult, or slow speed technical riding. Typical examples include low-speed obstacles, mud pits, getting stuck, and several attempts to continue. In these scenarios, the dirt bike radiators are not getting enough airflow to keep the coolant cool enough.

The dirt bike radiator fan kits are an excellent way to keep your dirt bike running cooler and over time prevent excessive heat related issues.

Most dirt bikes will have a model specific radiator fan kit that installs directly into the radiator frame. They hook up into the existing wiring typically using a plug under the tank or the seat.

You can also use a universal dirt bike radiator fan kit that installs directly into the radiator and uses wiring connectors to hook up into power.

Newer TPI dirt bikes have incorporated the dirt bike radiator fan into the ECU (engine controller unit), which turns the fan off and on automatically. Most KTM and Husqvarna models 2020 and up use this method and its easy to install them into the radiator and plug in to an existing wiring connector.

Here are few popular dirt bike radiator fan kit models that you can choose from. Both Tusk and Trail Tech universal dirt bike radiator fan kits are reliable, easy to install and worth the time and money to keep your dirt bike cool.

For a perfect fit and for newer TPI dirt bike models, you should stick with the model specific dirt bike radiator fan kits as they plug in directly to the existing wiring harness and sometimes uses the existing ECU to control the temperature on/off switching.

Tusk Digital Radiator Fan Kit

This kit is universal, and fits most dirt bikes with some wiring work.

Trail Tech Radiator Fan Kit

Universal fan kit from Trail Tech. Higher quality than Tusk, and fits most dirt bikes.

KTM/Husqvarna Fan Kits

Newer KTM and Husqvarna dirt bikes have ECU controlled radiator fans. Check your model for a good fit first.


Dirt bike radiator fan kits work really well and they effectively prevent the dirt bike engine from overheating.

Therefore, if you ride slow and technical trail riding or hard enduro type trails, you should install a dirt bike radiator fan to your dirt bike.

Dirt bike radiator fan kits are easy to install, require no maintenance or tinkering and perform extremely well. You can also ask your dealer to install the dirt bike radiator fan to your new dirt bike.

Keep it cool and plow through!

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