Motorcycle Coolant and Cooling Systems – Everything You Need to Know

by Karen Neill

Motorcycle Maintenance

How Does a Motorcycle Cooling System Work?

Liquid-cooled systems, found on larger motorcycles and high-performance models, use a coolant (antifreeze) to absorb engine heat and transfer it to a radiator. The coolant circulates through passages within the engine block and cylinder head, absorbing heat. A water pump keeps the coolant flowing. The hot coolant travels to the radiator, a network of thin tubes with fins. Airflow passing through the radiator fins cools the coolant down. A thermostat regulates coolant flow. When the engine is cold, it restricts flow, allowing the engine to reach operating temperature quickly. Once hot, it opens, allowing coolant to circulate freely through the radiator. In a nutshell your cooling system is all about circulation. Getting the coolant moving around your engine at the right time and in the right place.

Motorcycle coolant, also known as antifreeze, plays a vital role in regulating your engine’s temperature. It prevents overheating in hot weather and protects the engine from freezing in cold climates. Here’s a deep dive into motorcycle coolant:

Motorcycle Cooling System Diagram

Types of Motorcycle Coolant

  • Ethylene Glycol Based Coolant: This is the most common type. It’s a mixture of water and glycol, offering freeze protection and good heat transfer. There are two main subtypes:
    • Inorganic Acid Technology (IAT): The traditional green coolant, containing silicates that can form a protective layer inside the radiator. However, these silicates can degrade over time.
    • Organic Acid Technology (OAT): A newer coolant using organic acids for corrosion protection. OAT coolants are longer-lasting and better for aluminium engines but can be more expensive.
Motorcycle Cooling
  • Waterless Coolant: This coolant eliminates the water component, offering a higher boiling point and improved heat transfer. However, it’s more expensive and requires a complete system flush before use.

Choosing the Right Motorcycle Coolant

  • Consult Your Owner’s Manual: Different motorcycles have specific coolant requirements. Using the wrong coolant can damage your engine.
  • Consider Your Climate: If you live in an area with extreme temperatures, an OAT coolant or waterless coolant might be better.
  • Material Compatibility: Ensure the coolant is compatible with your motorcycle’s engine materials, especially aluminium.

Confused by Coolant Colours?

All Coolants are now colour-coded, pink, blue, yellow, orange & green and although this seems like a great idea – each specification has a different colour – this is not the case It turns out that each manufacture has its own colour coding for coolant, each manufacturer has its own colour-coding system for its coolants so the only way to tell what colour your bike needs is to look into the reservoir.  This is something the industry needs to get together on and agree on to make life easier for maintenance.

Maintaining Your Coolant

  • Regular Checks: Inspect your coolant level regularly, typically before each ride. Refer to your owner’s manual for the proper coolant level.
  • Coolant Life: Coolant degrades over time, losing its anti-corrosion properties and freezing protection. Consult your manual for recommended replacement intervals, typically 2-4 years.
  • Topping Up: If your coolant level is low, only use a pre-mixed coolant of the same type already in your system. Never add plain water.

Coolant Safety Precautions

  • Coolant is Toxic: Keep it out of reach of children and pets.
  • Disposal: Don’t pour coolant down the drain. Take it to a hazardous waste disposal facility.
  • Spills: If you spill coolant, clean it up immediately with a spill absorbent and dispose of it properly.

By understanding these aspects of motorcycle coolant, you can ensure your engine operates at the optimal temperature, preventing overheating and extending its lifespan. Remember, if you’re unsure about any aspect of your coolant system, consult a qualified mechanic.

Leave a Comment

Member of Institute of the Motor Industry (IMI)
Member of Retail Motor Industry Federation (RMI)
Member of National Motorcycle Dealers Association (NMDA)
Haringey Council Contractor