Bubbles in Power Steering Fluid: Symptoms, Causes and Fixes

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?

What Causes Bubbles In Power Steering Fluid

air pressure in power steering reservoir

The power steering fluid, cooling systems, differentials, and transmission fluids are designed to function at high temperatures.

Does power steering fluid boil? Yes. The power steering fluid boils at a very high temperature of about 600 degrees. However, this boiling shouldn’t prompt bubbling.

What do I mean? Some vehicles function optimally by displaying a little boiling point in the power steering reservoir. Others do not show any boiling sign at all (a good example is ford escape 2014).

While little boiling with quietness is expected in some vehicles, a boiling with some noise indicates a real problem that needs professional attention. Even if you don’t have a bubbling power steering fluid, if it gets too hot, it can get burnt, losing its lubricating power to oil the steering components and creating a whining or groaning noise when the system is running.

If you suspect and after proper diagnosis, it proves that you have a burnt fluid, consider flushing the fluid as soon as possible.

Why is my power steering fluid boiling? The primary reason for a boiling or bubbling power steering fluid is air getting pulled into the system. Once the air gets into the steering system, it finds its way to the steering fluid reservoir.

Now you may be wondering, ‘how do I get aerated power steering fluid?’ Air gets into the power steering fluid via;

  • A cracked power steering fluid reservoir
  • Leaks in the low-pressure line.
  • A leak in the power steering suction.

The most commonplace that air usually goes into the power steering reservoir is between the pump and the hose that connects it with the reservoir.  Typically, the power steering fluid goes into the pump via a suction. If you have a loose or bad connection, the suction will draw air into the system.

Air in the power steering fluid causes noise and a spongy steering feel. Once the foaming power steering fluid goes into the reservoir, you will have a bubbling power steering fluid.

Other causes of bubbles in power steering fluid.

Most times, what we see as air bubbles are not truly air bubbles but are boiling due to overheating in the steering systems.

Power Steering pump

A failing or lousy power steering pump will grind shavings and worn bearings, thereby generating too much heat. The steering fluid will start bubbling and may even rise in the reservoir. In rare cases, the fluid will overflow as you turn the steering wheel lock to lock.

Pinched hose

A pinched steering hose or line can cause hydraulic pressure to return into the reservoir. This will display the appearance of bubbling.

Low flow

Low fluid will lose the capacity of expelling heat from the fluid reservoir, leading to overheating and bubbling of the remaining fluid.

Rough driving

Quick-lock to lock or swinging of the steering wheel will cause the pump and steering gearbox to overheat and bubble.

power steering fluid moving in reservoir

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 includes;

  • 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.

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.

Q: What happens if there’s air in 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 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.

Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

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