Understanding and Diagnosing Power Steering Noise

Power Steering is the best feature that hit the market in 1951 and forever changed the game. In the old days you had to “put a shoulder into it” while today you can easily accomplish a full steering wheel rotation with a finger.  How is this done? Let’s take a look at the components that work together to create this magic. Hopefully we can get into understanding and diagnosing power steering noise.

What is the Purpose of the Power Steering and its Components?

Power Steering (also known as power-assisted steering) is your invisible daily partner that helps you steer faster, more precisely and easier. It makes parking and low-speed maneuvers easy even if you drive a heavy vehicle. It does this with the help of hydraulic power or electric power or sometimes both.

Generally a typical setup includes : a sensor attached to the steering wheel, a drive belt between the crankshaft and the power steering pump, a pump, a rack and pinion unit and hoses.Power Steering is the best car related invention since 1951.

Power Steering Pump
– is turned by an accessory drive belt and creates pressure in the power steering hose high side. This pressure is pushed to the input side of the power steering control valve.
Rack and Pinion – represents the unit that turns the front wheels when the driver turns the steering wheel. As the name implies it has 2 components: a pinion gear and a steering rack.  When the steering wheel is turned, it rotates the pinion gear that pushes the rack in the desired direction.
Power Steering Hoses – are composed by 2 main steering hoses – the high side and the low side.
These are attached with threaded brass fittings to the rack and pinion. More exactly, the high side hose comes attached to the power steering pump, while the low side hose comes attached to a small pipe. The high side carries fluid under pressure to provide the power assist while the low side carries back the low pressure fluid to the pump.

How does it all work?

The pump is activated via a drive belt which is turned by a pulley on the crankshaft and provides pressurized power steering fluid to the rack and pinion unit. The driver turns the steering wheel (provides input), the pinion turns against the rack and pushes it in the desired direction. Meanwhile, in many applications, the steering wheel sensor also picks up the input information and transfers the information to the power steering control valve. This valve manages the fluid pressure to one side of the piston, which assists the driver in turning easier.

 if the power steering runs low on oil, the lack of lubrication can cause whining or moaning noise when the wheel is turned

Power Steering Noise

The power steering is made up of many components that communicate with each other through pinions, dampers and joints. In order to run effectively they need to be kept in good lubrication conditions.

For example if the power steering runs low on oil, the lack of lubrication can cause whining or moaning noise when the wheel is turned. Also neglected belts tend to slip and create a loud screeching noise. Any noise produced while steering should concern all vehicle owners.

Trapped air in the power steering circuit can greatly reduce it's performance and make it noisy.Diagnosing Power Steering Noise

There are various situations which can create power steering noise. For example, a screeching noise is a sure sign of power-steering belt wear. If you notice that screeching noise only occurs from time to time, then it is a good indicator that you should check the belt to see it’s condition and/or tension.

If your power steering belt slips-off or breaks you will end up with a ‘hard to control’ car and depending on the circumstances when this happens, it could be life threatening .

Whining  sounds can be heard both on road as well as when just idling. Most of the times this is an indicator that sooner or later, the system will fail. The sound is rather unique to each car, being a mix of a whirring and whining sound that will vary with the speed of your engine and/or with input from the steering wheel. Once you hear it, you won’t forget it. There are 4 instances in which this sound can appear:

1. This might happen because there is a small issue in the design of your pump and this could or could not affect your pump in time. Manufacturers are known for sometimes creating noisy power steering pumps, however sometimes it could be from tight tolerances in your particular pump. Hearing this sound without any other leaking fluid spots, wobbly pulley or loss in power steering indicates that you are most likely safe. There is an easy fix to this which we will cover later in the article.

2. The same noise can appear if you have air trapped in the system. If the pump catches air bubbles is can start to cause whining noises and vibrations. Since these are extremely hard to diagnose, it’s safer to flush and change your power steering fluid with fresh, manufacturer approved, power steering fluid.

3. Whining can appear also when the wheels are being turned to one direction or another. As bearings go bad and start to make noises, you will also experience leaks around the pulley and/or pump area, difficulty in turning the wheel when stopped or a wobbly pulley. This is a sign of a failing power steering pump. Be careful, since experiencing these symptoms together indicates that the time to replace your power steering pump is just around the corner.

4. Whining can also appear because of low fluid levels. Power steering fluids tend to be forgotten and it’s no surprise that most vehicle owners are surprised when they discover that the fluid level is low. Low fluid translates into low lubrication between the components. The power steering assembly contains multiple components that work together and power steering fluid as the only element or liquid between these metals. If the level is too low for some time, the components can start to heat, turn blue and ultimately weld themselves together. This could prove to be extremely dangerous as handling would be virtually non existent. Moreover to change the entire power steering system would require a small home loan, most vehicle owners preferring to change the car instead of the power steering.

Groaning noises can also appear and these are the worst noises a steering pump can make. As the pump continues to fail, the groaning gets worse. These noises often appear only when driving at low speeds and making turns. These can also indicate low fluid levels and should be checked as soon as possible. If the power steering system fails because of low fluid levels it can damage the whole system including the steering rack and lines.

This problem can be eliminated just by checking the power steering fluid level once every other engine oil change and to use a quality additive in order to keep them properly lubricated thus having a very smooth steering wheel experience.

Rattling, clicking or clunking noises are usually symptoms of worn joints in the steering linkage or front suspension. Over time, these joints that allow the steering column to transfer the directions from your steering wheel to your rack and pinion, tend to become loose or worn. A way to test is while at a complete stop, move the steering wheel left to right in order to feel how much it moves without the wheels actually moving outside. If there is a great free-movement or you hear some clunking or clicking noises then your joints and/or bushings definitely need to be replaced. However, sometimes these sounds can hide something more complex and significant that might need a mechanics attention.

Power Steering PumpFixing Power Steering Noise

Power steering noise, when ignored, can lead to major problems and permanent damage to the rack and pinion or the entire system. Repair of the power steering system is usually recommended to be left in the hands of professionals because of the complexity of the system.

There are instances where instead, what you could ‘boost’ up the lubrication to the power steering components that in turn, will make it smoother and keep it more protected. Providing proper lubrication levels will also reduce heat and friction to help the movements between components smoother and quieter. This is merely a preventative step, however, and replacement of the power steering pump, pulley, rack and pinion may still be necessary and even recommended for those who have been delayed in repairing the cause of the problem. These lubricants can sometimes save you a good amount of money… or at the very least, buy you some valuable time because they form a protective film that prevents serious damage even if you happen to have a leak you don’t know about or very low fluid levels.

In terms of lubricants, one very good example is Boost Performance Product’s CleanBoost® EMT™ Engine and Metal Treatment. This product is formulated with stabilizing anti-oxidants, compounds and special metal deactivators that ensures the smooth performance of any hydraulic system. When applied, the fluid in the power steering system carries Engine and Metal Treatment to the asperities of the metals to form a covalent, galvanic bond on it. It provides 2 to 4 micron penetration into the surface, therefore lessening heat and friction and quieting power steering noise where applicable. Often times this treatment represents the difference between a burned out power steering pump and a power steering pump that only needs to be topped up with oil.

For more information about this product, simply head here.

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Tech Guy

Automotive enthusiast, passionate about Jeeps, hot-rods, turbos, performance, efficiency, diesels, fuels, high performance oils, additives and anything with an engine.

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