Power Steering Stiff at Low RPM – What's Wrong?

Your power steering is a great helper in your everyday driving. Have you ever tried driving a car that wasn't equipped with power steering? Although this technology is not new and became the industry standard long ago, some of us remember those cars that were very tough to steer, especially at slow speed.

But what should you do if suddenly your power steering becomes stiff at low RPM? This is not the most pleasant experience and you may be frustrated once you notice this. I will explain everything - just make sure you read this carefully.

In short, the stiff power steering at low RPM may be the consequence of low power steering fluid, a bad pump, a broken steering rack, or malfunctioning electric steering. The set of possible problems depends on the type of power steering technology you have in your vehicle. Also, the age and mileage of your car are to be considered.

Let's find out what can happen and how you should deal with this!

Symptoms of problems with your power steering

Before we go on with the reasons and possible fixes for this problem, I want to describe the possible symptoms so that you knew that you are on the needed page. So, in this article, I'm describing the problem of the power steering that usually shows up in hydraulic systems but sometimes may also appear in electric steering systems.

The problem has the following symptoms:

• when you drive, everything seems to be quite OK, nothing special;
• when you stop the vehicle and the engine starts idling, the steering wheel becomes surprisingly tough to turn;
• sometimes, it's almost impossible to turn at all;
• if you press the gas pedal and the engine will rev up, the steering wheel will unblock and work as usual;
• when you are driving slowly for a long time (about 10 MPH or slower), the steering wheel feels stiffer than usual;
• the problem can disappear from time to time, but, in most cases, it bothers you quite often.

So, the steering wheel feels too stiff when the engine RPM falls. This may disturb you from driving because you will not be able to turn when needed and you will need to apply different levels of power to your steering wheel each time. And it's not safe at all to drive the car like that.

Let's see what can cause these problems and how you should react.

What are the reasons for the stiff steering wheel at low RPM?

Given there are two common types of power steering systems, the reasons for this problem may be different. I will try to figure out reasons for both electric and hydraulic power steering but some of them will still influence only one type of the system.

Here are the most common reasons for stiff power steering at low RPM:

1. Power steering pump is failing

The main unit in the hydraulic power steering system is the pump. This unit creates pressure and ensures that the fluid is circulating through all the pipes and passages in the system. When needed, the pump makes the pressure higher and actually does some job in helping you steer the vehicle.

The power steering pump should be efficient to make the entire unit work well. It's usually driven by the serpentine belt (also called the drive belt - the one that drives the alternator). And the rotations of the pump directly depend on the RPM.

If the pump is old and worn out, it may work well at high RPM but create low pressure or no pressure at all at low RPM. It explains why your power steering may feel stiff at low RPM. If you have hydraulic steering, this is the most common culprit.

Unfortunately, checking it and repairing the pump is not that easy. Usually, the power steering pump should be replaced if it acts like this.

2. Inappropriate power steering pump

I personally had this problem after a small accident. My original pump was bent and couldn't be repaired, so I bought the new one for my old Chevy. Of course, as a person who doesn't like spending money, I chose the aftermarket pump made by a brand I had never heard about. And it acted just like this: at low RPM I could barely turn the steering wheel but at high RPM everything was perfect.

So, I had to buy the OEM pump after that and have it installed once again which took me much more money than I originally planned to spend. This was a good lesson.

3. Low level of power steering fluid

This reason will also affect only hydraulic power steering. If your car is equipped with this system, you will see the power steering fluid reservoir under the hood of your car. Look at it and you will easily identify if the fluid is on the right level. There are MIN and MAX marks. Before you add some fluid, make sure that it's compatible with your vehicle!

Also, looking at this reservoir may give you more information about the pump. Start your car, open the hood, and locate the reservoir. Do you see the fluid like boiling in it? It usually means that the pump is dead and it sends the pressure the wrong way.

4. Serpentine belt is slipping

Again, this will most likely affect the hydraulic power steering but can also have an effect on electric systems. The serpentine belt is not eternal. It will need replacement at least once every 90,000 miles or even more often. If it's not replaced when needed, it may start slipping.

When the drive belt slips, it doesn't rotate everything that it has to rotate. First of all, it has to rotate the alternator that supplies your vehicle with electricity. So, it can affect the electric power steering system. But if it slips, it will certainly affect the hydraulic power steering unit because the pump will just stop working.

The belt may slip when idling or when driving at low RPM, so it's pretty likely that this problem has to be considered in your case.

5. Problems with electric power steering

Electric power steering is supposed to be more durable and reliable than hydraulic systems. You don't have a pump here, there is no fluid or something that can leak. But the system also has several common problems.

Here they are:

• the power steering relies on the alternator and can fail when the alternator is faulty;
• the electric power steering system is controlled by control units that may glitch;
• it relies on several sensors and this also adds to the chance of failing;
• very often, electrical power steering systems throw codes and messages and stop working for many various reasons.

I recently had this problem in one of our fleet cars, the Ford Fusion. It just said "Power Steering Problem, Drive with Care" and I felt that the steering became stiffer. I had to go to the dealership and they found out that the problem was in some sensor that was connected to the power steering system. And the Fusion had only 50K miles on it.

So, electric power steering can also fail, and finding the reasons for it being stiff is not that easy. Very often, you will need professional help for this.

Can you drive if the power steering is stiff at low RPM?

Although there is a big chance of damaging the steering system when this happens, you can drive after you make sure there are no serious problems with the pump. In most cases, the problem will require immediate repair, but still, there is no need to call a tow truck.

Here's what you will have to do before you keep driving:

• if your car has electric power steering, read all the error messages and do as they say;
• if the electric power steering is stiffer but still comfortable to use, you may carefully drive to the repair shop or dealership;
• if your car has hydraulic power steering, you should stop the car, turn off the engine, and open the hood;
• locate the power steering fluid reservoir and check if the level is OK (please only add ATF that is recommended by the manufacturer if needed);
• if the level is OK, start the car without closing the hood and then look at the reservoir - if the fluid is "boiling", driving further is not recommended.

If everything seems to be OK and the steering wheel is not deadly locked but just becomes stiffer when idling or driving at low RPM, you may keep driving but you should immediately plan the visit to the good repair shop.

Final thoughts

Unfortunately, the power steering system is not the most durable unit in your vehicle. And it's going to malfunction at certain mileage or after certain conditions.

If you get into this unpleasant situation when the power steering works poorly at low RPM, you should check everything you can just like I described in this article. This will help you understand if it is safe to move forward on your own. If you find out that the power steering in your car has huge problems, better call a tow truck and pay a hundred bucks for your safety.