Air Cooled vs Liquid Cooled – ATV Engines

When it comes to off-roading on all-terrain vehicles (ATVs), keeping the engine cool is important for good performance and keeping the ATV running for a long time.

Two primary cooling methods dominate the ATV market: air cooling and liquid cooling.

While both systems serve the same purpose, they employ different mechanisms to keep the engine cooled. In this post, I’ll go into the differences between air-cooled and liquid-cooled ATVs, exploring their benefits, drawbacks, and the factors to consider when choosing the ideal cooling system for your next ATV.

What Is An Air-Cooled ATV Engine?

An air-cooled ATV engine is a type of cooling system that relies on the flow of air to dissipate heat generated by the engine. Air-cooled engines utilize a series of metal fins attached to the outer area of the engine cylinder and sometimes the cylinder head as well. These fins increase the surface area available for heat transfer and serve as channels for air circulation.

As the engine runs, it makes heat due to the burning of fuel. The cooling fins on the engine’s surface help in absorbing this heat. When the ATV is in motion, air goes through these fins and the heat is carried away, thus cooling the engine.

Some ATVs are more advanced than others when it comes to air-cooling, for example, some have fans or ducts to force the air through and better cool the engine. The fans are helpful at lower speeds or sitting still, as the ATV may not get enough air flowing over the cylinders when not moving or moving slow.

There are some ATVs that use an oil-cooler to cool the engine. It’s a step above being purely air-cooled, but not as good as liquid-cooling.

What Is An Liquid-Cooled ATV Engine?

A liquid-cooled ATV engine uses a more complex cooling system that has a liquid coolant to regulate and dissipate heat from the engine. The system consists of a radiator, water pump, coolant fluid, and hoses. The coolant, typically a mixture of water and antifreeze, is circulated throughout the engine and parts that need it.

When the engine is running, the coolant is pumped through the engine and the coolant absorbs the heat and carries it away to the radiator. The radiator is a system of multiple long tubes and fins, these fins are similar to the air-cooled, but you have a lot more of them and thus more surface area. The coolant runs through the tubes and fins, where a fan is blowing on them to cool the coolant and send it back to the engine to get heated again.

A liquid-cooled engine can better control how warm the engine runs by how fast the coolant runs or how fast the radiator fans move. It’s because of this that liquid-cooled engines last longer and are more fuel efficient.

A liquid cooled engine is a completely closed system of pushing coolant around tubes to keep the engine cooled. The best thing about a liquid-cooled engine is that it works far better, especially at lower speeds, to keep the engine cooled.

Air-Cooled Engines

Below, I’ve listed the pros and cons of air-cooled engines.

Pros of Air-Cooled ATV Engines:

  1. Simpler, lower maintenance.
  2. Cheaper and most often found on low-end ATVs.
  3. Fewer things to break.
  4. Easier to work on.

Cons of Air-Cooled ATV Engines:

  1. Not the best at dissipating heat, especially at lower speeds.
  2. They tend to run hotter and parts of the ATV engine wear out quicker because of it.
  3. Cooling ability is limited to the ATV size, so you don’t see large displacement engines use air-cooling.
  4. Noisier and more vibration, mostly because they’re on cheaper model ATVs.
  5. Run hotter and burns more fuel than a similar liquid-cooled engine.

Liquid-Cooled Engines

Below, I’ve listed the pros and cons of liquid-cooled engines.

Pros of Liquid-Cooled ATV Engines:

  1. Better at heat dissipation.
  2. Consistent temperature, especially at lower speeds.
  3. Better cooling means more powerful engines on smaller ATVs, as it can handle the cooling better.
  4. Run quieter, but can get loud if running the ATV hard and the radiator fans turn on at full blast.
  5. More fuel efficient.
  6. Less heat on the driver and passenger on the ATV.

Cons of Liquid-Cooled ATV Engines:

  1. More complex with more moving parts.
  2. Heavier due to needing more parts to cool the engine.
  3. Cost more.
  4. More maintenance and care is needed to keep it working correctly.
  5. Coolant leaks and overheating.

Oil-Cooled Engine

Between air-cooled and liquid-cooled ATVs engines is the oil-cooled engine.

The oil-cooled engine circulates the ATV’s engine oil through a radiator, like you would with coolant for a liquid-cooled ATV. What’s different is that oil is used, and it’s slightly simpler than a liquid cooled system.

Some oil-cooled engines don’t have a radiator fan, and the radiator is often small in comparison to a liquid-cooled engine.

You can add a fan to your oil-cooler to get better cooling for your ATV, but it won’t be as good as a liquid-cooled engine. In most cases, an oil-cooled engine is only slightly better than being fully air-cooled.

Most Common Cooling System?

Today, it’s more common to find liquid-cooled ATVs, especially on newer and larger engine ATVs.

Air-cooled ATVs are still around, but they tend to be on 400cc or lower ATVs. You mostly find air-cooled engines on kids ATVs or affordable ATVs you buy online*. Even these kids and cheaper ATVs are starting to move to a basic type of liquid-cooling.

Most people want liquid-cooling, so the manufacturers are moving towards that, it’s just like the move to fuel-injected ATVs over carbureted models.

Older ATVs tend to be air-cooled, so it might be the only option if you’re buying a used ATV. But even ATVs from the 90s and early 00s still had liquid-cooled engines options.

How To Keep An Air-Cooled Engine Cooler

If you have an air-cooled ATV, you’re maybe wondering how to keep your engine cooler. I’ve listed the many things you can do to keep your ATV engine running cooler, even though it’s air-cooled.

  • Maintain a good airflow, remove any accessories or dirt that blocks air from getting to the engine. People often block the front with a winch and plow, find a way to get more airflow with the winch in the way.
  • Check your oil and keep it in good range and change it when it needs it. Consider using synthetic oil.
  • Take breaks when you can, you need to cool yourself down too, so turn the ATV off when you take breaks.
  • Avoid heavy loads and riding the ATV too hard.
  • Keep moving and cruise when you can.
  • Consider adding an aftermarket cooling fan to your air-cooled ATV.
  • Do regular maintenance. Dirty oil, air filter, and chain can lead to your engine working harder and thus heating up more.
  • Avoid riding on hot days and locations.

What To Do If Your ATV Is Overheating?

There are several reasons why your ATV may be overheating, and in this post I go over the many reasons and what you can do about it.

If your smells hot, you go here.

Wrap Up

When it comes to ATVs, ensuring proper engine cooling is important for optimal performance and longevity. Air-cooled and liquid-cooled systems are the two primary cooling methods used in ATVs.

While air-cooled engines are simpler, lighter, and easier to maintain, they may struggle with heat dissipation under heavy loads and at lower speeds. On the other hand, liquid-cooled engines offer superior heat dissipation, consistent performance, and increased power output, but they come with added complexity, weight, and maintenance requirements.

It ultimately is up to you and your riding style when picking an air-cooled or liquid-cooled ATV. If you ride hard, long and need a workhorse, then go with a liquid cooled ATV. If you want a simple, easy, and just a basic ATV, go with air-cooled.