Kart Radiator Maintenance – The Complete Guide

The radiator on your go kart plays a vital role in the health and performance of your engine. The radiator serves as an element to keep the engine cool, much like the one found on road cars. However, on karts they are built to a much smaller scale, but kart radiators still require maintenance.

Kart radiator maintenance is quick and easy, and it should be done consistently if you want to preserve your engine. Proper radiator maintenance is often overlooked by drivers. Nevertheless, it plays a critical role to your engine’s health, performance, and lifespan.

Drivers can also alter the radiator with some simple tricks which will allow their engines to warm up much faster. This is useful when racing in colder temperatures, however you need to be careful not to overheat the engine. Let’s take a closer look at kart radiator maintenance below.

What Is A Kart Radiator?

A kart’s radiator has one main function, and that is to keep the engine cool. The radiator is found in front of the engine, and it looks like a large rectangular grid that is sat on the side of the kart. A go-kart’s radiator is very exposed, especially when compared to a car.

Karts don’t have big engines. However, they do operate under huge amounts of stress in order to achieve maximum performance. A go kart’s engine can quickly overheat, especially if the radiator is faulty or damaged.

Keeping The Engine Cool

The radiators serve as a cooling device for the engine. When traveling at higher speeds, the grid can funnel air into it which helps with engine cooling. In addition, a coolant liquid is used to help keep control over the engine temperature.

Unlike standard car radiators, a kart’s radiator does not have a fan. This means that if the kart is not moving, it will be unable to keep the engine cool and get rid of hot air. This is an important factor to remember when you are sat in the pits.

Maintenance Is Key

For this reason, radiators are crucially important to the health of your engine. If you are driving with a cracked radiator or one that is not well maintained, you could be putting your engine at risk of overheating and seizing up.

It’s just as important to consistently replace your radiator fluid. If the coolant levels are too low, your engine will also be overheating. You should regularly flush and refill the radiator to keep the coolant fresh.

Why Is Kart Radiator Maintenance So Important?

A kart’s radiator is responsible for keeping the engine cool when it is running. If the radiator is damaged or not properly maintained, it could lead to a complete engine failure. This means you would need to buy a whole new engine. The engine is obviously a very expensive component, so you want to avoid having to replace it at all costs.

Many drivers tend to overlook radiator maintenance because they have never had an issue with it. However, you can only overlook it for so long until your engine begins to give you problems. You may experience a couple of problems if you have a faulty radiator.


First, you will experience extreme levels of overheating on your engine. If you don’t have a Mychron device, this could also go unnoticed until it is too late. Without the Mychron device there is no way to monitor your engine temperature while driving, or even while you are in the pits.

The engine temperature warning light on the Mychron is easily the most important feature on the device. When the engine temperature warning light goes on you need to stop your kart immediately or risk severe engine damage.

A faulty radiator can cause the engine temperature light to switch on quickly. Normally, the light should not go on at all. However, if the light goes on while you are in the pits or even out on track, you should take a serious look at your radiator.

Lack Of Power

Another problem you might experience is a lack of power from your engine. This could be on the long straights or out of slow corners. If your engine is unable to stay at its optimum temperature, it will struggle to perform well.

If your radiator is faulty is will also affect the lifespan of your go kart’s engine. Your engine will become permanently damaged which means that you will not be able to compete with it for much longer. You will also see a reduction in value if you choose to sell your kart later down the line.

Can You Cool Your Engine Too Much?

However, cooler is not always better. Engines have an optimum operating temperature. Of course, in summer months more cooling will be needed to keep the engine temperatures at their optimum level.

On the other hand, winter months and cooler climates need less cooling in order to keep the engine at its optimum temperature. This becomes a tricky situation for drivers who experience both extremes in ambient temperatures.

Too Little Cooling

If the engine is undercooled, the engine could overheat. Just like with any other engine, if it’s not kept cool, it can end up overworking. An overheating engine can fail due to the extreme temperatures building up inside of it.

Too Much Cooling

If the engine is overcooled, then parts can begin to seize up. This happens when the engine is pushed too hard before it reaches its optimum temperature. Some parts within the engine need to reach a specific temperature before they can begin to work harder.

In a way, it is very similar to human muscles. If you push your muscles too hard before they are warmed up you can experience cramping, similar to an engine seizing up. If you overwork your muscles they could fail from exhaustion, resulting in sprains, pulled muscles or even muscle tears. This is similar to an engine overheating, causing parts to wear out very quickly.

As a general rule of thumb, Rotax recommends the water temperature for summer months to be between 120-125oF (48-52oC). In the winter months however, it is recommended to keep the water temperatures between 131-140oF (55-60oC).

How To Use The Radiator To Improve Your Engine Performance

Your kart’s radiator can be used as a tool to improve your engine performance. Since it is used to control the temperature of your engine, you can use the radiator in various ways to your advantage compared to your competitors.

In professional leagues with experienced competitors, everyone will be using these in one form or another. However, in amateur leagues most people do not know how crucial the radiator is to the kart’s engine performance.

Choosing The Correct Radiator Size

Radiators come in different sizes in order to compensate for different climates. For hotter ambient temperatures where the engine needs to be kept cool, larger radiators are often used. The larger radiators have more surface area which allows more airflow into them and therefore extra cooling power for the engine.

On the other hand, for colder ambient temperatures, smaller radiators are available. The smaller surface area lets in less air which helps to keep the engine temperature higher. This also allows the engine to warm up much faster in the cooler conditions.

Air Screens

An air screen is a simple sheet that is fitted to the top of your radiator. It can be pulled down and adjusted as needed. This is a convenient solution versus changing radiators based on the outdoor temperatures which could change multiple times over the course of a day.

The air screen can be pulled down to cover as much or as little of the radiator as you need. Therefore, you are in full control of the surface area of the radiator. In other words, you can control when your engine cools down and when it heats up. This is useful for race days. You can completely close the air screen on your out lap, blocking airflow into the engine entirely.

This will get the engine up to temperature much faster than your opponents. When your engine reaches its optimum temperature, you can simply open your air screen before you begin to push the engine. Opening the air screen allows the airflow back into the radiator, allowing it to cool the engine again.


Many drivers don’t have the budget to buy any extra gadgets for their karts. Luckily, there is a much cheaper alternative that does the same job. However, it is less flexible to use than an air screen. The solution here is to use duct tape.

Just standard duct tape can do the trick, and it is still used by many drivers. Simply stick the duct tape over the radiator horizontally. Starting from the top will be the most effective. It acts the same way as an air screen does, reducing the surface area of the grid, letting in less air.

However, you cannot adjust it while you are driving, so make sure that you do not put too much duct tape on your radiator. Having too much duct tape on it will cause the engine to overheat as it will not be able to suck in enough air to effectively cool the engine down.

Using Your Hand

If you don’t have an air screen and you don’t have access to duct tape you can also simply use your hand to cover up the radiator. You may see some drivers doing this on their out laps. The radiator is close enough to the driver so that if you simply rest your hand on it you can cover up some of the surface area.

The most effective place to do this is on the straights since that is where most of the air will be flowing into the radiator. Do not try to do this through corners. You may lose control of the kart and spin out.

This technique is quick enough to be able to do it multiple times per lap. It is also quite effective in warming up the engine, and it will definitely help you when the ambient temperature is cooler than usual. Just always make sure you remain in control of your kart.

How To Diagnose A Damaged Radiator

A damaged radiator can cause you a lot of headaches, especially in the long run. If you have a faulty radiator, you may experience some issues with your kart. More importantly, it can lead to long-term permanent damage to your engine.

You can identify damage to your radiator in a few different ways. The first is through your driving experience. If you find that your engine is constantly overheating it could be related to the radiator. This could either be radiator damage, or a lack of cooling fluid.

You may also experience a lack of power on the straights or even coming out of slower corners. While this could be due to other issues with the kart or even just having the incorrect set up, it could also be related to a damaged radiator.

Inspecting Your Radiator

The second way of diagnosing radiator damage is by inspecting it. You may find rust on the radiator itself, or even on the inside radiator cap. Depending on how much rust you find on the radiator, it could be an early sign of damage.

There could also be some cracks showing up on the radiator. This is due to the excessive forces that are put through the chassis on some circuits. A cracked radiator can lose a lot of its efficiency and therefore lack the ability to cool the engine.

How To Maintain Your Kart’s Radiator

Radiator maintenance is crucial to keeping your kart running at its maximum performance and making the engine last as long as possible. If you don’t properly maintain your radiator, you could suffer an engine failure or a seized engine.

Firstly, you need to flush your radiator regularly. This can be done once a week, or once every two weeks depending on how often you drive the kart. Flushing the radiator is a very quick and simple process.

Flushing Your Radiator

At the bottom of the radiator, you will see a pipe which is clamped onto the radiator. In order to flush the radiator, you can simply undo the clamp and let the old water and coolant run out of the radiator.

When you flush your radiator, it’s important to remember that there is no water or coolant in it. Some drivers tend to forget this as they run about doing other tasks, and driving a go-kart with no water or coolant in the radiator is a recipe for disaster. A good idea is to set a reminder on your phone or create a ‘No Water’ sign that you can stick to your steering wheel.

Look For Cracks

While the radiator is flushing, make a habit of inspecting the entire unit for cracks. As soon as you see a crack starting to form, no matter how small, you need to replace the radiator. Cracks will only become bigger as time goes on, and it’s not worth risking the entire engine.

When you refill the radiator make sure you secure the outlet pipe first. It is highly recommended to use distilled water to refill the radiator. You can use tap water, but most tap water contains various minerals that can leave deposits inside the radiator. Over time, this leads to rust and radiator damage.

Use High-Quality Coolant

Always make sure that you use a good quality engine coolant as well. You may need to use different types depending on the seasons and the ambient temperatures. Some coolants are designed to keep your engine running at specific temperatures.

Always try to ensure that you keep your engine running within the recommended temperatures noted above. When you are storing your kart for the off season, it is crucial that you still care for the radiator. If your off season is during the winter and the temperatures become extremely low, you can use anti-freeze to protect your engine. This is an easy way to winterize your kart.

If the temperatures remain high, then using distilled water is a good idea. Using tap water may cause rust and corrosion on your radiator when you are not using the kart for longer periods of time.

Final Thoughts

Many drivers overlook their kart’s radiator. However, it plays a vital role in engine performance and reliability. Keeping your radiator properly maintained is key to the longevity of your kart’s engine. By flushing your radiator regularly and checking it for damage, you will stay on top of your kart’s radiator maintenance and ensure your engine lasts as long as possible, performing at its best.