Power Steering Fluid Bubbles: 7 Common Causes and Solutions

Power steering has become an essential feature in modern vehicles, significantly easing the effort required to maneuver and control the car. 

It provides drivers with the necessary leverage to steer the vehicle smoothly, enhancing both comfort and safety during the journey.

A common issue encountered with power steering systems is the formation of bubbles in the power steering fluid, which can lead to reduced system performance and even potential damage.

This blog post aims to delve into the seven primary reasons behind power steering fluid bubbles and provide effective solutions to address them. 

By understanding these causes and how to tackle them, you can ensure the longevity and optimal performance of your vehicle’s power steering system.

Reasons Your Power Steering Fluid Bubble

1. Low Fluid Level

The power steering fluid plays a pivotal role in the system, ensuring the smooth transmission of power from the steering wheel to the car’s wheels. 

Acting as a hydraulic fluid, it facilitates the movement of pistons in the power steering pump, which in turn aids in turning the wheels with minimal effort.

A low fluid level can result in the introduction of air into the system. When the fluid level drops below the necessary minimum, the pump starts sucking in the air along with the fluid, forming bubbles. These bubbles can result in erratic steering behavior, a condition known as ‘foaming.’

To avoid such scenarios, checking and maintaining the power steering fluid level regularly is crucial. This can be done using the dipstick in the power steering reservoir, ideally when the engine is cold. 

If you find the fluid level low, you should top it up with the appropriate power steering fluid as your car’s manufacturer recommends. 

Regular checks and timely fluid top-ups are small steps that can significantly contribute to the longevity and efficiency of your power steering system.

2. Leaks in the Power Steering System

Leaks in the power steering system can also lead to the formation of bubbles in the power steering fluid. 

Various components in the system can potentially develop leaks, including the hoses, fittings, and seals.

  • Prone Points to Leaks

The power steering hoses transport the fluid throughout the system, and any damage or wear can result in leaks. 

Similarly, the fittings connect different parts of the system and must be secure to prevent leakage. 

The seals, particularly those around the power steering pump and gear, are also subject to wear and tear, which can result in leakage over time.

  • Leaks Introducing Air into the System

Leaks in these components can introduce air into the fluid. When there’s a leak, not only does the fluid escape but air can also get sucked in due to changes in pressure within the system. 

This air can lead to foaming and the formation of bubbles in the power steering fluid, which can disrupt the optimal functioning of the system.

  • Regular Inspections and Maintenance to Prevent Leaks

To prevent these issues, it is advisable to conduct regular inspections of your power steering system, paying particular attention to the hoses, fittings, and seals. 

Look for signs of wear, damage, or leaks, and take corrective action promptly to replace the faulty components. 

Maintenance activities such as regular checks, timely repairs, and replacements can go a long way in preventing leaks and ensuring that your power steering system continues to operate smoothly and efficiently.

3. Contaminated Power Steering Fluid

Fluid contamination in the power steering system is another common issue that can arise. This contamination originates from dirt, debris, and other minute particles infiltrating the system. 

The contamination can occur when carrying out maintenance or repair activities, especially if these procedures are not conducted in a clean environment. It can also be a result of deteriorating internal components of the system.

  • Contaminated Fluid and Bubbling 

When the power steering fluid is contaminated, it can form bubbles and foaming, akin to air getting introduced into the system. 

The foreign particles in the fluid can disrupt the flow, creating air pockets that can eventually form bubbles. 

This bubbling can significantly hamper the optimal functioning of the power steering system, leading to stiff steering and reduced efficiency.

  • Flushing and Replacing Power Steering Fluid

To prevent issues associated with fluid contamination, it is crucial to flush and replace the power steering fluid regularly. 

This process involves draining out the old, contaminated fluid and then refilling the system with fresh, clean fluid. 

The frequency of fluid replacement depends on the manufacturer’s recommendation and the condition of the system. 

However, as a general rule, it is advisable to flush and replace the power steering fluid every 50,000 miles or every two years, whichever comes first. 

Regularly undertaking this simple maintenance task can significantly enhance the longevity and performance of your power steering system.

4. Aeration and Aggressive Driving

  • Aeration in the Power Steering System

Aeration is a phenomenon where air mixes with the power steering fluid, forming bubbles or foam. 

This typically happens when the system operates under strain, such as during aggressive driving or continuous hard turns. 

  • Impact of Aggressive Driving and Continuous Hard Turns

Aggressive driving behaviors, including sudden starts, abrupt stops, and hard turns, can strain the power steering system. 

This strain can lead to the aeration of the fluid, disrupting the flow and reducing the system’s effectiveness. 

Continuous hard turns, in particular, can cause the fluid to churn, leading to air pockets and bubbles forming, thereby affecting the performance of the power steering system.

  • Driving Techniques to Reduce Aeration and Potential Damage

Adopting proper driving techniques is essential to prevent aeration and subsequent damage to the power steering system. 

It’s best to avoid sudden starts and stops as much as possible and use smooth, gradual movements when steering. 

Also, avoid holding the steering at the extreme left or right for extended periods. These practices can help maintain the integrity of the system, ensuring a smooth, responsive steering experience and prolonging the lifespan of the power steering system.

5. Malfunctioning Power Steering Pump

  • Role of the Power Steering Pump in the System

The power steering pump plays a vital role in the overall functioning of the power steering system. It is responsible for generating the necessary hydraulic pressure to assist in steering the vehicle. 

The pump achieves this by pushing the power steering fluid into the steering gear, which then applies the necessary force to move the wheels in the desired direction.

  • Faulty Pump and Fluid Cavitation

If the power steering pump malfunctions, it can cause fluid cavitation and bubble formation. Cavitation refers to the formation of vapor cavities within the fluid. 

This occurs when the pump is unable to adequately supply the fluid due to mechanical issues such as wear or damage, leading to a drop in pressure. 

The resulting cavities or bubbles can disrupt the fluid flow, thereby reducing the system’s efficiency and effectiveness.

  • Potential Solutions for a Malfunctioning Pump

Diagnosing a malfunctioning power steering pump involves checking for symptoms such as a whining noise while steering, a stiff steering wheel, or fluid leaks around the pump area. 

If these symptoms are present, the pump may be malfunctioning. Potential solutions include checking the power steering fluid level, refilling if necessary, and ensuring the pump’s drive belt is in good condition and correctly adjusted. 

If these steps do not rectify the problem, replacing the power steering pump may be necessary. Always consult with a professional mechanic for accurate diagnosis and repairs.

6. Worn Seals or O-rings

Seals and O-rings in the power steering system play a crucial role in maintaining the system’s integrity and functionality. 

They serve to prevent the leakage of power steering fluid, ensuring that the system maintains the necessary pressure for optimal operation. 

  • Seals and O-rings in the Power Steering System

Seals and O-rings essentially create a closed, high-pressure system allowing the power steering pump to perform its function effectively. 

They are designed to withstand the steering system’s constant pressure and temperature changes. 

Without them, the fluid will leak out, and the necessary hydraulic pressure needed for steering assistance will not be maintained.

  • Impact of Worn Seals Allowing Air Entry into the System

Worn or damaged seals and O-rings can allow air to enter the power steering system. This air results in bubbles in the hydraulic fluid, a phenomenon known as cavitation. 

Cavitation can decrease the hydraulic efficiency of the power steering system, resulting in steering issues such as noise and stiffness. 

  • Identifying and Replacing Worn Seals or O-rings

Identifying worn or damaged seals and O-rings involves checking for signs of fluid leakage around the pump and the power steering system. 

If leaks are found, it is likely that the seals or O-rings are worn out or damaged and need replacement. 

However, replacing the seals and O-rings in the power steering system is a complex task that a professional mechanic should handle. 

This process involves disassembling the power steering pump and other components, which necessitates technical knowledge and expertise. 

Always consult with a professional mechanic for these repairs to ensure the longevity and performance of your power steering system.

7. Reservoir Cap

The reservoir cap in a power steering system plays a crucial role that extends beyond merely covering the reservoir. 

Its primary function is maintaining a proper seal, ensuring the system remains airtight, and the hydraulic fluid remains free from external contaminants.

  • Importance of a Properly Sealed Reservoir Cap

A properly sealed reservoir cap forms an integral component of the high-pressure environment within the power steering system. 

It prevents the ingress of air and potential contaminants, which can degrade the hydraulic fluid and compromise the system’s efficiency.

  • Risks Posed by a Damaged or Improperly Sealed Cap

A damaged or improperly sealed reservoir cap can introduce unwanted air into the system. This can lead to cavitation and bubbles in the hydraulic fluid, similar to the scenario where worn seals and O-rings are present. 

The result is a decrease in hydraulic efficiency, which can manifest as noise, stiffness, and other steering issues.

  • Checking and Replacing the Reservoir Cap

Regularly checking the reservoir cap for any signs of damage or improper sealing is a simple, yet effective preventive measure. 

If the cap is found to be damaged, loose, or ill-fitting, it should be replaced immediately to ensure the integrity of the power steering system. 

While it may seem like a minor component, a properly functioning reservoir cap is essential for the optimal performance of your power steering system.


In conclusion, the occurrence of bubbles in the power steering system can stem from seven primary reasons, ranging from the use of incorrect or low-quality power steering fluid, the presence of worn seals and O-rings, to a damaged or improperly sealed reservoir cap. 

These issues can introduce air and potential contaminants into the system, leading to cavitation and decreased hydraulic efficiency.

It is crucial to address these issues promptly to prevent further damage and maintain the optimal performance of your power steering system. 

Failure to do so can result in noise, stiffness, and other steering issues, which can complicate driving and potentially lead to unsafe conditions.

Regular maintenance and inspections form a significant part of preventive measures. Checking components like the reservoir cap, seals, and O-rings regularly, coupled with using the correct power steering fluid, can go a long way in ensuring the integrity and efficiency of your power steering system. 

So, don’t underestimate the power of regular upkeep – your car’s performance and safety depend on it.

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