Can You Use Automotive Power Steering Fluid In A Boat?

You’re out on your boat and suddenly realize you’re running low on power steering fluid. You don’t have any boat-specific fluid, but you have some automotive power steering fluid in your tool kit. You start to question whether you can use it on a boat.

It depends on the boat and the type of fluid you have. While some boat manufacturers may recommend using a specific type of power steering fluid, others may allow for using an automotive power steering fluid in a pinch.

Here, we’ll explore the differences between automotive power steering fluid and boat-specific power steering fluid and the potential risks and benefits of using automotive fluid in a boat.

Before selecting whether to utilize automotive fluid in your boat’s power steering system, we’ll go over some crucial considerations. Continue reading to find out more!

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What is Automotive Power Steering Fluid?

A type of hydraulic oil called automotive power steering fluid is used to transmit force from the steering wheel to the steering mechanism of a vehicle. It guarantees effortless and smooth steering and is a crucial part of power steering systems.

Purpose of Automotive Power Steering Fluid

A power steering fluid’s main functions are to lubricate the system’s moving elements and supply hydraulic pressure for the wheels’ steering assistance. Without power steering fluid, turning the steering wheel would be difficult to handle since it would take a lot of effort from the driver.

The viscosity of Automotive Power Steering Fluid

Viscosity is a metric for a fluid’s flow resistance. In automotive power steering fluid, it is essential for maintaining effortless and smooth steering. The viscosity of the power steering fluid is determined by the thickness of the fluid, which is measured in centistokes (cSt).

Most automotive power steering fluids have a viscosity between 7 and 12 CST. This range is optimal for power steering systems as it ensures the fluid flows smoothly and transfers force effectively without causing excessive wear and tear.

Boat Power Steering Fluid vs. Automotive Power Steering Fluid

Boat power steering fluid and automotive power steering fluid are two different fluids designed for specific applications. While automotive power steering fluid is designed for car use, boat power steering fluid is explicitly formulated for marine engines.


The primary difference between boat power steering fluid and automotive power steering fluid is the environment in which they are used.

Boats are subjected to harsher conditions than cars, with exposure to saltwater, humidity, and high temperatures.

As a result, boat power steering fluid is formulated with different additives and viscosity stabilizers to protect the steering system in these conditions.

Additives and Viscosity Stabilizers

The boat power steering fluid is formulated with special additives and viscosity stabilizers not found in automotive power steering fluid. These additives are designed to protect the steering system from the harsh marine environment and to ensure smooth, responsive steering.

One of the key additives found in boat power steering fluid is an anti-corrosion agent. These substances shield the metal steering system parts from rust and corrosion brought on by saltwater exposure.

Anti-foaming components are also present in boat power steering fluid to stop the formation of air bubbles, which could impair performance and harm the steering system.

Boat power steering fluid is prepared with viscosity stabilizers in addition to these additives to provide consistent performance across a wide temperature range. Boats are often used in cold and hot environments, and the power steering fluid must maintain its viscosity and performance.

The Risks of Using Automotive Power Steering Fluid in a Boat

Using automotive power steering fluid in a boat can have serious negative consequences. While it may seem like a cost-effective and convenient solution, it is essential to consider the risks involved. Here are some of the potential risks of using automotive power steering fluid in a boat:

Damage to the power steering system

The special parts of a boat’s power steering system are not intended to be used with automotive power steering fluid. The improper fluid can seriously harm the system, necessitating expensive repairs or perhaps total power steering failure.

Safety issues while out on the water

The power steering system is a critical component of a boat’s steering system, and using the wrong fluid type can compromise its effectiveness. This can create serious safety issues while out on the water, particularly in rough conditions where accurate steering is essential.

Viscosity issues

A boat’s power steering system may not receive the level of lubrication and protection required by automotive power steering fluid due to its viscosity being different from that of boat power steering fluid. The system may become increasingly worn out over time as a result, which could accelerate system breakdown.

Corrosion and rust

Automotive power steering fluid may contain different additives and chemicals that can cause corrosion and rust in a boat’s power steering system. Over time, this can result in further harm and degradation.

It’s crucial to remember that utilizing the incorrect type of power steering fluid might void the boat’s power steering system’s warranty from the manufacturer. To avoid these risks, using the correct type of fluid explicitly designed for use in boats is crucial.

Alternatives to Automotive Power Steering Fluid for Boats

If you want to avoid the risks of using automotive power steering fluid in your boat, you have a few alternatives to consider.

The boat power steering fluid is designed specifically for marine applications and is the best option for your boat’s power steering system.

Here are some other compatible fluids that you can use in place of automotive power steering fluid:

Marine hydraulic fluid

This high-quality fluid is designed for use in hydraulic systems, including power steering systems in boats. Marine hydraulic fluid has excellent lubricating properties and is resistant to water and corrosion.

Automatic transmission fluid

Many boat manufacturers recommend using automatic transmission fluid in the power steering system. This fluid has similar viscosity and additives to boat power steering fluid, making it a good alternative.

Synthetic power steering fluid

Some synthetic power steering fluids are compatible with boat power steering systems. These fluids offer superior performance and protection and are ideal for high-performance boats.

Using the recommended fluids for your boat’s power steering system can offer many benefits. These fluids offer your boat’s power steering system the best possible performance, longevity, and protection.

They offer improved lubrication and corrosion resistance, which helps your power steering system last longer and prevents costly repairs. Additionally, using the right fluid may preserve your boat’s dependability and safety, making sailing easier and less stressful.


For the safety and lifespan of your boat, it is crucial to use the right power steering fluid. Although it might seem like an excellent alternative, power steering fluid for vehicles lacks the chemicals and viscosity stabilizers necessary to protect a boat’s power steering system from corrosion and other damage caused by exposure to water and salt.

Using the wrong fluid can have serious effects, including steering failure or system component damage that can be unsafe and expensive to replace.

Therefore, in order to preserve the durability and secure operation of your boat’s power steering system, it is imperative to use boat power steering fluid or other compatible fluids advised by the manufacturer. You may have a safe and worry-free sailing experience by taking the essential steps and utilizing the right fluid.

Jack K. Pride
Jack K. Pride

Jack K. Pride is an accomplished author and a prominent figure in the boating community. With a passion for boats and a deep understanding of the maritime industry, he has been sharing his expertise through his compelling articles on

Known for his insightful and informative writing style, Jack's articles provide valuable insights, tips, and knowledge to boat enthusiasts worldwide. His dedication to the subject matter and commitment to delivering high-quality content makes him a trusted voice in the boating world.

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