Coolant & Other Fluids

Specialised Fluids for Specialised Systems

Modern vehicles and equipment rely on more than engine oil and conventional driveline lubricants. Cooling systems, hydraulic brakes, power steering and motorcycle suspension all depend on specialised fluids designed around the operating requirements of the particular system.

AMSOIL specialty fluids include coolant and antifreeze, synthetic brake fluid, power steering fluid and motorcycle fork oils. Although these products serve very different purposes, they share an important principle: the correct fluid should be selected according to the system's specification and application rather than appearance, colour or a familiar viscosity alone.

Coolant & Antifreeze

Engine coolant transfers heat away from the engine while protecting cooling-system components against corrosion, freezing, boiling and deposits. Modern cooling systems use a variety of coolant technologies and manufacturer-specific requirements, making compatibility an important consideration when servicing or topping up a system.

Coolant colour should not be treated as a specification. Similar colours can represent different coolant chemistries, while compatible products may use completely different dyes. Check the vehicle manufacturer's coolant requirements before selecting a replacement.

Brake Fluid

Brake fluid transfers hydraulic pressure from the brake controls to the braking components and must remain dependable across a wide range of temperatures. Common glycol-based brake fluids also absorb moisture over time, progressively reducing their boiling-point performance and making periodic replacement an important part of brake-system maintenance.

DOT 3, DOT 4, DOT 5 and DOT 5.1 are not simply successive quality grades. In particular, silicone-based DOT 5 differs fundamentally from the glycol-based fluids commonly used in modern braking systems, while DOT 5.1 should not be confused with DOT 5 despite the similar name.

Power Steering Fluid

Hydraulic power steering systems use fluid to transmit pressure while lubricating pumps, steering gears, valves and other internal components. Fluid requirements vary between vehicles: some specify dedicated power steering fluid, while others require a particular automatic transmission fluid or manufacturer-specific hydraulic fluid.

Many newer vehicles use electric power steering and contain no hydraulic steering fluid at all. Identifying the steering-system design and required fluid specification is therefore an important first step before servicing the system.

Motorcycle Fork Oils

Motorcycle fork oil performs both lubrication and hydraulic damping functions within the suspension. Its viscosity influences how fluid moves through suspension valving, meaning the oil selected can directly affect compression and rebound behaviour.

Nominal fork-oil weights such as 5W, 10W and 15W are not necessarily directly comparable between different lubricant manufacturers. For suspension tuning or when changing brands, published viscosity data can provide a more useful comparison than the nominal weight printed on the bottle.

The Correct Fluid Matters

Specialty fluids should not be substituted simply because two products look similar or appear to have comparable viscosity. Different systems can require particular friction characteristics, additive chemistry, material compatibility, hydraulic behaviour and temperature performance.

Always follow the vehicle, equipment or component manufacturer's specification and service procedure. Use the AMSOIL Vehicle Product Finder to identify suitable AMSOIL fluids for supported applications.