A bubbling or boiling power steering fluid indicates a real problem in the system! Every vehicle is designed with several system components that use fluid to function correctly.
Regardless of where these fluids are used, all of these components use fluids that resist boiling.
The cooling system, for example, operates at a high temperature to complete this feat and prevent the fluid from boiling. The same applies to power steering fluid.
In this article, we’ll discuss the causes of bubbles in power steering fluid, what to do when you notice it, and how to get rid of bubbles in the power steering fluid. Could you take a seat and follow me religiously?
Understanding Power Steering Fluid
To comprehend power steering fluid and its role in your vehicle’s operation, it’s essential to grasp its function and significance in the power steering system.
Power steering fluid is a hydraulic fluid that transmits power in the steering mechanism, ensuring smooth and easy steering control.
Function of Power Steering Fluid
Power steering fluid serves as a vital element in your vehicle’s power steering system, enabling the seamless transmission of hydraulic power to maximize steering performance.
It lubricates and reduces friction within the system, enhancing the overall steering experience.
Significance of Proper Fluid Levels
Maintaining the correct level of power steering fluid is crucial for optimal system functionality.
Inadequate fluid levels can lead to increased friction, causing components to overheat and potentially fail. Regularly check and top up your power steering fluid to ensure smooth steering operation.
Circulation and Cooling Process
Power steering fluid circulates through the system, facilitating power transfer from the steering wheel to the wheels. This circulation also aids in cooling vital components within the power steering system, preventing overheating and damage.
Common Issues with Power Steering Fluid
Issues such as bubbling power steering fluid can indicate underlying problems within the system.
Air bubbles in the fluid may result from leaks, aeration, or a malfunctioning pump. Addressing these issues promptly is crucial to prevent further damage to the power steering system.
Maintenance and Care
Routine maintenance, including flushing and replacing the power steering fluid as recommended by your vehicle manufacturer, is essential to ensure the longevity of your steering system.
Following maintenance schedules and using the correct type of fluid are key steps in preserving the health of your power steering system.
Understanding the basics of power steering fluid and its importance in your vehicle allows you to take proactive steps in ensuring a well-functioning steering system.
By being mindful of fluid levels, system circulation, and maintenance practices, you can enhance the longevity and performance of your power steering system.
What Causes Bubbles In Power Steering Fluid?
The most likely reason why your power steering fluid is bubbling is either a leak in the low-pressure return line or a crack somewhere in the power steering reservoir.
However, there are other ways that air can get into the system. Even if you flush all the fluid and replace it, you’ll still need to find where the leak is coming from to keep bubbles from redeveloping again.
#1. A Leak in the Power Steering Low-Pressure Return Line.
The power steering return line isn’t always as robust as the high-pressure side and can crack, letting air into the system and causing bubbles to appear in the reservoir.
The hose is usually made from NBR tubing (Nitrile Butyl Rubber), which has superior resistance to petroleum products.
When it’s new, it can handle pressure up to 150 PSI. Though NBR can get stiff and brittle with age, allowing tiny cracks to form, which could let in air.
As the power steering fluid moves back from the rack or steering gear through the low-pressure line, it gradually returns to normal atmospheric pressure. This allows the air bubbles to expand, making the fluid look frothy.
Usually, when the low-pressure power steering return line starts to leak, fluid goes out as air comes in.
If you follow the line with your hand, you’ll eventually find a leak with tiny drips of power steering. If the power steering fluid lands on something hot, it will smoke, giving off a strange burnt smell like burned marshmallows.
#2. A Leak in the Power Steering Pump.
A leak in the power steering pump is another common way air can get into the system, causing bubbles in your power steering fluid.
Here again, the air gets in and circulates through the system, gradually mixing into a froth that makes the steering stiff and unresponsive.
A significant volume of air could rush in depending on where the leak occurs. The most common point of failure is at the junctions where the hose transitions to the hard line. However, it’s also possible for the pump’s housing to crack.
A leak in the power steering pump is usually obvious, as pressurized fluid will spray out of the pump. It’s usually right under the reservoir, though some cars have the pump and reservoir separately.
Other signs of a leak in the power steering pump causing bubbles in the fluid include a whining noise when you first turn the car on and steering that gets stiff in a hurry. This is usually a sign that a major leak is letting fluid out and air in.
In some newer models, a severe leak might trigger a check engine or power steering light. When it does, the ECU will also throw a code you can check on an OBD II reader.
Code P0551 is for “Power Steering Pressure Sensor Circuit Range/Performance.”
#3. A Crack in the Fluid Reservoir.
The plastic of the power steering fluid reservoir can crack or suffer a puncture that allows air into the system, causing bubbles.
In a case like this, the leak is usually low down in the reservoir, allowing tiny gasps of air to be sucked in by the high-pressure line of the power steering pump.
When this happens, you’ll notice the bubbles in the power steering reservoir, and if you pull one of the lines, the fluid that comes out will be frothy.
The bubbles will settle if you let the car sit with the engine off for an hour or two. At that point, the fluid level in the reservoir will be very low. You might even be able to spot a hairline crack in the white semi-translucent plastic.
#4. The O-Ring on the Power Steering Input or Output.
The power steering input and output lines have O-rings that can slowly fail, allowing small amounts of air into the system and creating bubbles in the power steering fluid.
If it’s the output O-ring, the pressure of the fluid will let some fluid escape, and you’ll see it leaking on the power steering pump.
Though if it’s the input O-ring, air can seep into the system, and the low-pressure/atmospheric pressure might not make the leak obvious.
At least not until the O-ring completely failed. At that point, you would have a noticeable fluid leak drizzling down into the engine bay.
#5. A Bad Hose Clamp on the Return Line.
The low-pressure return line usually has a hose clamp that secures it to the reservoir/power steering pump.
If the clamp had come loose or got bumped when you were working on something else, it could let a tiny amount of air into the reservoir, making little bubbles.
These bubbles could gradually get sucked into the high-pressure side of the system, making the steering increasingly stiff just a little bit at a time.
This is a problem that is often slowly developing. You might not notice a major change in the car’s steering at first as the pump is inclined to draw in fluid from the bottom of the reservoir, and the small bubbles are inclined to float to the top.
As the volume of air suspended in the fluid steadily increases, more bubbles are drawn in, causing the power steering to become progressively stiff. By the time you notice it, the problem looks more serious than it did initially.
#6. Improper Bleeding.
If you’ve recently performed a DIY power steering fluid change but accidentally let some air in the system, it could show up as bubbles in the reservoir and the lines.
In a case like this, a stray air bubble from improper bleeding passes through the power steering pump’s impeller, where it is whipped up into a froth that keeps circulating through the system.
Assuming it was a minor air bubble in the system, the amount of froth would be small. Yet it would also pervade the system, causing the steering to feel stiff.
You’d notice the stiffness most when you turn the wheel on a sharp corner to lock at low speed. You might even get a high-pitched whine from the power steering pump itself.
Symptoms of air in power steering fluid
Here’s the air in power steering symptoms you should watch out for. A common sign of air in the power steering is a sound of a mildly disgruntled cat in the engine compartment. The whining or groaning noise gets louder when you make an intensive steering wheel turn.
The moment your power steering begins to groan or moan, check the fluid level and color. If the bubbling reduced intensively and calms after topping the fluid, you are lucky.
But if the bubbling returns and probably the noise comes back, it is likely, you have a leak somewhere, and the air is pulling inside via the leaking spot.
Other signs you should watch out for include;
- Low and foamy reservoir fluid
- Growling or grunt noise at low maneuvers when turning
- Bubbles in the power steering fluid
- Leaks in the steering system
- Hard or stiff steering wheel.
Effects of Bubbling Power Steering Fluid
Recognizing the effects of bubbling power steering fluid is crucial in understanding the potential issues that may arise in your vehicle’s power steering system.
By paying attention to these effects, you can take appropriate action to address the underlying causes and ensure the optimal functioning of your power steering. Here are some common effects associated with bubbling power steering fluid:
#1. Increased Steering Effort.
When your power steering fluid is bubbling, it may lead to a noticeable increase in steering effort. This means that turning the steering wheel can become harder and require more strength than usual.
If you experience this effect, it’s essential to investigate the potential causes promptly to prevent any further damage to the power steering system.
#2. Noisy Steering Operation.
Bubbling power steering fluid can result in noisy steering operation, commonly manifesting as whining or squealing sounds when turning the steering wheel.
These noises indicate that air may be present in the system or that the fluid is not circulating correctly. Ignoring these sounds can lead to additional complications, so addressing this issue promptly is advisable.
#3. Foamy Fluid in the Reservoir.
One visible effect of bubbling power steering fluid is the presence of foamy or aerated fluid in the reservoir.
The formation of foam indicates that air has entered the system, causing the fluid to aerate and produce bubbles. This foamy fluid can hinder the proper hydraulic function of the power steering system, affecting its performance.
#4. Potential System Damage.
Continued bubbling of power steering fluid without resolution can potentially damage the power steering components.
The presence of air or contaminants in the system can cause increased wear on parts and compromise the overall efficiency of the system. Timely intervention is essential to prevent extensive damage and costly repairs.
#5. Steering Inconsistencies.
As a result of bubbling power steering fluid, you may experience inconsistencies in steering response and feel.
These inconsistencies can make steering less predictable and impact your ability to control the vehicle accurately. Resolving the underlying issues causing the bubbling fluid can restore smooth and consistent steering operation.
How To Fix Bubbling in Power Steering Fluid?
Let’s dive into the step-by-step guide to fixing the bubbling issue. You don’t need a fancy mechanic’s shop—just a little time and patience.
#1. Check the Fluid Level.
The first thing you should do is check the power steering fluid level. It’s simple:
- Open the hood and locate the power steering reservoir. It’s usually a small plastic tank near the front of the engine, often with a steering wheel icon on the cap.
- Remove the cap. Some caps have a built-in dipstick; others have “MIN” and “MAX” lines on the outside.
- Look at the level of the fluid.
If the fluid is low, add more using the exact type recommended by your car’s manual. Some cars need specific fluid types, so don’t guess!
Tip: If the fluid is dirty, dark, or smells burnt, it’s better to flush it out and replace it completely rather than just topping it off.
#2. Inspect for Leaks.
Bubbling often means there’s a place where air is leaking into the system. Now’s the time to do a careful inspection:
- Use a flashlight and check the hoses connected to the reservoir and steering pump.
- Look for any wet spots, cracks, or loose clamps.
- Don’t forget to inspect around the power steering pump itself for signs of leaking fluid.
If you find a small crack or loose clamp, it’s an easy fix—you can tighten clamps or replace hoses yourself with simple hand tools. However, if you find major leaks or damage to the pump, you might need professional help.
Tip: Even a tiny leak can cause serious bubbling because the system operates under pressure. Fixing even small issues early can save you hundreds of dollars later!
#3. Flush and Replace the Power Steering Fluid.
If your fluid is old or contaminated, it can trap air bubbles easily. Flushing the fluid is a smart move:
Steps to flush the system:
- Raise the front wheels off the ground using a jack. Make sure the car is safely secured.
- Disconnect the return hose (the one that sends fluid back into the reservoir) and point it into a large container to catch old fluid.
- Start the engine and slowly turn the steering wheel left to right while new fluid is poured into the reservoir.
- Keep doing this until you see clean new fluid coming out of the hose.
- Reconnect the hose, refill the reservoir to the proper level, and secure the cap.
Using clean fluid will not only fix bubbling but also extend the life of your steering pump and other parts.
Tip: Always use a fluid that matches your car’s manufacturer recommendations—wrong fluid can cause damage.
#4. Bleed the System.
After refilling with new fluid, there’s still a chance that air is trapped inside. Bleeding the system helps push that air out.
Here’s the easy way to bleed:
- With the car still jacked up, turn the steering wheel all the way left and right 20-30 times with the engine OFF. This moves fluid through the system without putting too much pressure on it.
- Check the fluid level again and add more if needed.
- Now start the engine and repeat the left-right turning slowly a few more times.
- Watch the fluid in the reservoir. If you see bubbles disappearing and the fluid looking smooth, you’ve successfully bled the air out!
Tip: Don’t rush! Turning the wheel slowly is important to avoid creating more bubbles.
#5. Replace Worn Parts If Needed.
If, during your inspection, you found cracked hoses, leaking seals, or a worn-out pump, those parts need to be replaced.
Here’s a simple guide:
| Problem | Solution |
| Cracked or brittle hose | Replace the hose |
| Loose or rusty clamps | Tighten or replace clamps |
| Worn pump seals | Replace the steering pump or rebuild it |
Replacing a hose is pretty easy for DIYers. However, if the pump itself is failing, it’s a bigger job and might require a mechanic.
Tip: If your steering feels heavy, whines loudly, or still shows bubbling after all your fixes, it could be a deeper pump or rack issue.
FAQs.
Q: How do you get rid of bubbles in the power steering fluid?
If you notice the signs above and after a thorough diagnosis, it proves you have air trapped in the power steering system, there are two ways to get it out. The methods are through the steering bleeder valve and the lock-to-lock turning.
Let’s look at the first method;
- Turn off the engine and allow it to cool
- Take off the reservoir cap and inspect the level
- Top up the steering fluid if needed
- Trace the bleeding valve on the steering rack and pinion or steering gearbox. If you have difficulty locating the Toyota power steering bleeder valve location or other vehicle models, trace the other end of the high-pressure line that travels from the power steering pump. You’ll find the other end attached to a steering rack.
- Insert a hose on the end of the bleeder valve and input the other end into a catch pan.
- Start the vehicle
- Gently open the bleeder valve
- Turn the steering wheel Lock to lock a couple of times
- Switch off the vehicle
- Tighten the bleeder valve
- Refill the fluid reservoir with fresh fluid.
- Inspect the fluid in the steering pan and repeat the procedures if you notice air bubbles.
The second method involves;
- Raise the front wheels with a floor jack and support it jack stands
- Remove the reservoir cap
- Inspect the fluid level and top it if needed
- Get into the driver’s seat and steer the wheel lock to lock repeatedly.
You need to continue this lock-to-lock turning until there’s no air bubble coming out. What happens if there’s air in power steering?
Q: What happens if there’s air in the power steering?
The power steering system functions via hydraulic principles, and air affects any hydraulic system if it pulls into it. Once air makes its way into the power watering system, the pump will compress it, resulting in noisy and hard steering feels.
Q: How long does it take to get the air out of the power steering?
Whether you want to get the air out of the power steering by bleeding the system or by turning the wheel lock to lock, it requires time and patience.
If you choose to turn the wheel lock to lock, it’ll take about 50-60 lock-to-lock turns to expel trapped-in air out of the system.
In addition, you need be checking the state and fluid level while turning the steering wheel slowly. You must ensure the fluid reservoir cap is removed while turning the 50-60 lock to lock cycle.
In contrast, if you choose to expel the trapped in the air through manual bleeding from the rack and pinion steering, it will take you around 45 minutes to 2 hours.
Q: Is it normal for power steering fluid to boil?
A boiling power steering fluid indicates a real problem in the steering system. Boiling and bubbling power steering fluid denotes air in the system, which will result in noisy and difficult steering, especially in low maneuvers.
In any case, continuous driving with air in the steering fluid will cause premature power steering pump failure.
Q: Why is my power steering fluid brown and foamy?
Significant reasons for a brown and foamy Power steering fluid is contamination and air. As the power steering draws the fluid from the reservoir, it creates suction effects that could pull air into the system.
Inspect your steering system for damaged piping or busted hose, loose hose clamps, or leaks.
Final word
Having wrapped up the causes of bubbles in power steering fluid, effects, symptoms, and how to get rid of it, it is worth noting that driving with air in the power steering fluid will cause accelerated wear on the pump.
Whenever you notice air in your steering fluid, you need to act immediately. You can expel the air out using any of the methods above. In any case, I recommend the lock to lock process for a quick fix. If it doesn’t work in your case, use the bleeding method.