Can You Use Automobile Coolant in a Motorcycle?


You have plenty of automobile coolant in the garage, and you also need to change the coolant of your motorcycle. Therefore, can you use automobile coolant in a motorbike? Don’t make a rash to use the antifreeze; scrutinize the specifications of the coolant to know whether it’s safe to do so or not.

Can You Use Automobile Coolant in a Motorcycle?

It all depends on the specifications of the coolant. Some car coolants have ingredients that resemble those of automobile coolants.

So the best thing to do then is to compare the original manufacturer’s ingredients if it matches your bike coolant.

If the specifications differ, it isn’t safe to use the car coolant in the motorcycle.

What Ingredients Should it Have?

A car coolant is fit for a motorcycle engine if it meets the following criteria:

It Must Have Ethylene Glycol or Propylene Glycol

Generally, experts prefer propylene glycol to ethylene glycol as safer and effective. That’s because ethylene glycol is poisonous if you or your pet consume it.

The ethylene or propylene glycol coolant plays a vital role in the engine cooling of a motorbike, so long as you do not mix the two at any given time.

It Must Not Contain Silicates

Before using a car coolant in a motorcycle, make sure it doesn’t have silicates or phosphates. If you notice any traces of the two substances in the list of ingredients, then don’t use them on your motorcycle.

The engines of motorbikes have aluminum and magnesium. And silicates or phosphates may react with the metals and cause corrosion. In addition, the silicates aren’t suitable for the motorcycle engine seal.

There are abrasive particles in silicates that may eat away the gaskets and cause the leaking of a water pump.

Moreover, silicates encourage the building up of gels that might reduce the effectiveness of the temperature sensors.

Using the wrong coolant on the bike is likely to reduce its efficiency. So ideally, stick to what your motorcycle manufacturer recommends.

Are Automobile Coolants the Same as Motorcycle Coolants?

It all sums down to the list of ingredients; it may be the same or not. Usually, there are minor (but crucial) chemical differences between the two coolants.

Thus motorcycles require ethylene or propylene glycol-based coolants that have no phosphate or silicates. Otherwise, it’s best to stick to what your bike manufacturer recommends.

Types of Motorcycle Coolants

Motorcycle coolants fall under two categories;

  • Water-based coolants
  • Water-free coolants

Water-Based Coolants 

The water-based motorcycle coolants have water as one of the ingredients. You can either buy it premixed with distilled water or add water when you want to use it.

When you must mix it by yourself, stick to the correct ratio. Read the labeling to ensure that you abide by the instructions. Most often, you will need to combine water and the chemical in the ratio of 50:50.

This type of coolant is pocket-friendly yet offers satisfactory services to ordinary motorcycles. However, it exhibits a low boiling point and so not suitable for race bikes.

Before investing in a water-based coolant, ensure it has an anti-corrosion agent. Otherwise, the water component may cause corrosion of the motorbike engine.

Water-Free Coolant

As the name implies, its composition has no traces of water. For that reason, it doesn’t cause corrosion to the engines. Also compared to its water-based counterpart, it has the following advantages;

  • Corrosion-free
  • Last longer
  • Has a high boiling point

Therefore the coolant fits even extremely demanding engines that feature high revolutions such as the race bikes. Its only downside is in the price; it’s slightly expensive.

Is It Safe to Add Plain Water to the Motorcycle Radiator?

It’s safe to use water-based coolant, but not plain water. Using water only as the coolant of your motorcycle is not a wise idea.

It doesn’t matter whether it’s distilled or not; it will encourage the corrosion of the engine. Water-based coolants have additional chemicals to safeguard against corrosion. Further coolants have boiling points higher than that of plain water.

Is It Possible to Switch From One Motorcycle Coolant to the Next?

It’s possible to switch from one brand of motorcycle coolant to the next. But you first have to flash out the previous antifreeze from the engine thoroughly. As you may guess, it’s a demanding task.

Also if you accidentally add the wrong choice of a coolant to your motorbike, flush it out as soon as possible from the cooling system.

So What’s the Best Coolant for a Motorcycle?

The prudent thing to do is to stick to a coolant formulated just for a motorbike. And for that reason stick to what your bike manufacturer recommends. It can either be propylene glycol or ethylene glycol-based.

However, if you must use an automobile coolant, ensure its ingredients matches the specifications of the original motorcycle coolant. Further, it mustn’t contain silicates. Not any automobile coolant fits a motorcycle.

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