Does Power Steering Fluid Absorb Moisture? (Causes & Effects)

For optimum performance, you want the power steering fluid to contain nothing but the original fluid. However, this might not always be the case. How about moisture? Does the Power steering fluid absorb moisture? Is it hygroscopic? We’ll discuss this today.

Does Power Steering Fluid Absorb Moisture?

Yes, power steering fluid can absorb moisture over time. Most power steering fluids are formulated with additives that help them maintain their properties under high temperatures and pressures. However, these additives can break down over time, allowing the fluid to absorb moisture from the air.

How Can Moisture Enter the Power Steering System? 

Moisture can enter the power steering system through several avenues, primarily due to the system’s design and the materials used in its construction. Here are some common ways moisture can enter:

Breather vent

The power steering system is designed with a breather vent to allow air to enter and exit the system as the fluid level changes. This breather vent is often located on the power steering pump or reservoir. If the breather vent is not properly sealed or becomes clogged, it can allow moisture-laden air to enter the system.

Reservoir cap

The reservoir cap is another potential entry point for moisture. If the cap is not properly sealed or is damaged, it can allow moisture from the air to enter the reservoir and mix with the fluid.

Hoses and seals

The power steering system contains rubber hoses and seals that can degrade over time due to heat, pressure, and exposure to chemicals. As these components degrade, they can develop cracks or gaps that allow moisture to enter the system.

Read our guide on “Does Power Steering Fluid Damage Rubber” for more info.

Condensation

Temperature changes can cause condensation to form inside the power steering system. For example, if the vehicle is parked in a warm environment and then driven in cold weather, condensation can form inside the system, introducing moisture into the fluid.

Read our guide on “Can Power Steering Fluid Freeze“ for more info.

Contaminated fluid

If the power steering fluid becomes contaminated with water due to improper storage or handling, it can introduce moisture into the system.

Danger of Power Steering Fluid Absorbing Moisture

The danger of power steering fluid absorbing moisture lies in its potential to cause damage and malfunctions within the power steering system. Here’s a detailed look at the risks involved:

Corrosion

Power steering fluid is not inherently corrosive, but moisture in the power steering fluid can lead to corrosion of metal components within the system. This includes the pump, steering rack, and other metal parts. Corrosion can weaken these components, leading to leaks and eventual failure of the power steering system.

Reduced Lubrication

Moisture can degrade the lubricating properties of the power steering fluid. This can increase friction between moving parts, such as the steering rack and pump, leading to increased wear and potential damage over time.

Seal and Hose Damage

Moisture can cause rubber seals and hoses in the power steering system to deteriorate more quickly. This can lead to leaks and loss of fluid, which can cause the power steering system to operate ineffectively or fail completely.

Foaming

Moisture in the power steering fluid can lead to foaming. Foaming can reduce the effectiveness of the fluid in transmitting hydraulic pressure, leading to stiff or jerky steering.

System Malfunctions

Over time, the accumulation of moisture in the power steering system can lead to various malfunctions. These can include difficulty steering, noise when turning the steering wheel, and a decrease in overall steering performance.

How to Prevent Moisture from  Mixing With Power Steering Fluid?

Here are some straightforward methods to prevent moisture from mixing with the power steering fluid. 

• Perform regular checks of your power steering system, including the fluid level and condition. Look for any signs of moisture contamination, such as a milky or cloudy appearance in the fluid.
• Inspect all seals, gaskets, and hoses in the power steering system for signs of wear, damage, or leaks. Replace any components that show signs of deterioration to prevent moisture from entering the system.
• Ensure the reservoir cap is properly sealed and in good condition. Replace the cap if it shows signs of damage or wear.
• Check the breather vent for blockages or damage. Ensure it allows air to flow freely but is sealed to prevent moisture from entering.
• Use only high-quality power steering fluid recommended by the vehicle manufacturer. Store fluid in a clean, dry environment and avoid exposing it to moisture.
• Park your vehicle in a garage or shaded area to minimize temperature fluctuations, which can lead to condensation inside the power steering system.

How to Detect Moisture in the Power Steering Fluid?

Detecting moisture in power steering fluid can be challenging, as it often requires visual inspection and may not always be obvious. 

However, you check the color and clarity of the power steering fluid. Clean power steering fluid is usually clear or slightly amber in color. If the fluid appears milky, cloudy or has a frothy consistency, it may indicate the presence of moisture.

As per our experience, moisture-contaminated power steering fluid may have a distinct odor, often described as musty. If you notice an unusual odor coming from the power steering fluid, it could indicate the presence of moisture.

In addition, there are test strips available that can detect the presence of water in fluids such as power steering fluid. These strips change color in the presence of water, providing a visual indication of moisture contamination.