Ask a Technician: What Is That Squealing Noise I Hear When I Turn My Steering Wheel?

Unless you are driving an exceptionally old car, the sound will be related to the power steering in your car. This system is used on all new vehicles and as its name suggests, it assists with the steering.

A special pump is powered by a belt that runs off the engine. The pump pressurizes hydraulic fluid, which is then sent to the steering rack, usually behind the engine. When you turn the wheel a valve sends the fluid to one side of the steering rack, adding pressure to your steering input, while a return line takes the rest of the fluid back to the small fluid tank to be cycled through again.

These days, many cars have electrically powered assist steering (EPAS), which does away with the need for a pump to run the power assist, relying instead on an electric motor to assist with steering. This has the advantage of saving fuel because the pump is working all the time, even when you are driving in a straight line, so your steering is unlikely to squeal if you have such a system. Lynch Ford Chevrolet will be able to tell you what type of steering your car has.

But back to the main problem. There are two main reasons for a loud squeal coming from under the hood of your car. The first is that the drive belt to the pump is too loose, and when you use the power steering the belt slips and squeals on the pump pulley. The belt could also be fraying as it wears out, or even have some glazed sections on the belt where the grippy surface of the rubber belt has been ‘polished’ by friction.

The other main reason for steering noise is the pump itself. Check that the level of hydraulic fluid in the tank is OK. The fluid will usually be colored a red or pinkish color, the same as the cars transmission fluid (as a quick guide to diagnosing leaks on the driveway: coolant water is green, oil is yellow when new or black when used even slightly, and clear liquid is most likely from the air conditioning system draining the extra water that comes out of the air when it is cooled, which is perfectly normal).

If the pump is running on low levels of fluid your steering may also be harder to work than normal or work unevenly. The sound a worn pump usually makes is more of a whining growl than a squeal (turn the wheel as far as it will go and you will be able to hear the noise slightly, but this is normal). What is not normal is it occurring when the steering is not all the way over one side as far as it will go.

So it really depends on what sort of squeal is coming from the cars steering. If it is really, really loud and high pitched then it is most probably, and most commonly, that the drive belt is slipping on the power steering pump for some reason.