When should I change or flush my Power Steering in my Subaru?

One fluid that often goes neglected in a Subaru is the Power steering fluid, other than calling out the occasional inspection Subaru doesn’t really specify any real service interval and as such we have over the last few years dealt with more and more power steering fluid related symptoms.

The design of the 2000 and newer models creates a situation where old fluid can create power steering symptoms as well as take a toll on seals and internal components as well.  The fluid in the Power steering system is a hydraulic type fluid and in many applications automatic transmission fluid such as Dextron III is used.   There is not a drain plug for the fluid, the systems typically don’t have any type of filtering device and the fluid actually can become dirty pretty quickly.  The best way to deal with this is to flush out the fluid; at our shop we use a power steering flush machine with a flushing agent and some fluid conditioner when needed and offer to change out the fluid in the reservoir during a 30/60/90k service included if that’s al that is needed.  At home you can use a turkey baster to remove the fluid in the reservoir but you will have to do this, then re fill several times before you have even remotely clean fluid.

The newer model Subaru vehicles can suffer from old fluid over time taking a toll on the return line o-ring which can create a small air leak causing the fluid to become aerated, this will typically start out as a cold engine only symptom gradually becoming worse  and if not dealt with can eventually damage the power steering pump.

We have simply replaced the fluid on many H6 models from 2001 to 2004 to eliminate a cold engine growl or whine type noise being emitted from the power steering pump.   The 2000 to 2009 4 cylinder models can have an o-ring that will no longer seal when cold as a result of the fluid causing it to shrink over time and no longer seal until the o-ring warms up and expands into the sealing body of the power steering pump.

It has been a common repair for many years to reseal the power steering pump do to external fluid leaks (typically after many miles). On the 2000 and newer models we have observed less external leaks but more actual symptoms however,  which at a minimum require  you to replace the return line o-ring and perform a flush if there is a power steering type noise as a result of fluid aeration.

I would like to point out that a loose or worn power steering belt can cause noise and symptoms as well, please don’t automatically assume that after reading this article that you need to reseal your power steering pump

If you are a local customer and would like to schedule a power steering system flush you can do so below.

If you are somewhere else in the country or the globe for that matter and have a power steering type noise there isn’t much we can do for you over the phone that we haven’t already tried to address on the website under two separate articles this one and the other is here Power steering problems Explained.

I Hope this helps!

Justin

All Wheel Drive Auto