The Magical Effects of a Power Steering Flush (DIY for $7 or Less)

My car is getting old, and an older car means more maintenance. Worse, it's a turbocharged import, meaning work on it isn't cheap--my last major scheduled maintenance cost over $2000. So the fact my car had started having a few issues and my desire to put another 82,000 miles on it before even considering a newer model has driven me (no pun intended) to teach myself some basic and not-so-basic maintenance. The first success: flushing the power steering system--a task easier than changing the oil yet which had a big payoff!

Winter weather is rough on cars, and I'd been prepared to dismiss the slightly-jerky steering on my way to work each morning as a side-effect of the chilly temperatures. My car had also started idling a bit roughly, but hey, it was after all seven years and 82,000 miles old. Oh, and that vibration in the steering wheel around 45 mph? Probably tire wear or alignment, right? And the shops I took the car to checked all the fluids, didn't they?

Yet when working on a completely separate issue (more on that later), I noticed the power steering fluid was a yellow-orange color, when everything I'd read had stated the Forester's fluid should be red. Hmmm...

Jiffy Lube wanted $100+ to tackle the flush-and-fill on the power steering system. I can only imagine what a dealership would have charged! (The average price seems to run around $100, from what I can tell, with a range between $80 and $150.)  Enter a trip to my service manual and the Googles.

Confusingly enough (though stated so in the owner's manual and on the power steering fluid tank), the 2004 Subaru Forester XT's power steering system takes Dexron III automatic transmission fluid--not power steering fluid! I'd been considering flushing the system myself for a couple of weeks when I finally stopped at an auto parts store on the way home from work one day and picked up a couple of quarts of the stuff at a total cost of under $7.  Obviously, it pays to use what the manual actually calls for and not just look at the shelves and labels!

Though the full flush procedure involves a somewhat-tedious process (not one I expect the big-brand service centers actually complete, mind you--there's no way they do so along with everything else in a 20-minute service), there's a simple trick that does the job almost as well and with a fraction of the effort. Here's what you do:

1. Drive the car a bit to warm things up, then park on a reasonably level surface and shut off the engine.
2. Siphon out the existing power steering fluid straight from the reservoir (you could drain it by removing a hose, too). I used an all-purpose siphon hose, but a lot of DIY'ers claim a turkey baster from the dollar store works well, too.
3. Fill the power steering reservoir to the appropriate level (should be marked on the reservoir) with new lubricant.
4. Start the car, then turn the steering wheel all the way to the right and then all the way to the left several times.  This will help circulate the new fluid and remove air from the system.
5. Stop the car, and repeat steps 2-4 several more times.

The first time I flushed the system out, the fluid was a dark orange.  It wasn't gunky or burnt, but it certainly wasn't right, either.  After one flushing, the fluid still came out orange, even though what I'd poured in was deep red.  I repeated twice more, with each change of fluid coming out more and more red.  Overall, I didn't even use a full quart of fluid in this process.  You may need to repeat the process weekly if your power steering system is really dirty--after a week, though, my fluid is still nice and red.

No, it's not a true, full flush of the power steering system, but I can guarantee the typical big-brand service center doesn't do that, either, in the 20 minutes of "while you wait" work, either.  It got the job done for me, though.

What's amazing is that this simple bit of work, accounting for perhaps 10 minutes of this car maintenance novice's time, has had a huge impact on my car!  Gone is the jerkiness in the steering in the morning.  Better yet, gone is the rough idling: I suppose the fluid was dirty enough it was causing the power steering pump to strain a bit.  (Now, whether or not that means I have to change the whole pump out sometime in the not-distant future is an open question; if my fluid was bad enough to cause that much strain on the pump, might it not have done damage to it, too?)

I didn't even use the second bottle of Dexron III yet, so my real cost was $3.50.  That's a savings of at least $96.50 over what I'd have paid someone else to do it, and the process required no tools (well, the siphon, though I could have gotten by with a $1 turkey baster) and 10 minutes or less of my time.  And it had a noticeable effect on my car's everyday driving--nice!

After such a simple fix as my improvised power steering fluid flush, I feel empowered over my car, no longer in thrall to the mechanic's shop for anything short of a total engine overhaul.  Yes, I know my accomplishment was nearly effortless (an oil change would be more work, actually), but baby steps, baby steps!

Next up is a barely-more-challenging task: I'm replacing the stock intercooler hoses on my car with some fancy silicone ones from Samco.  No, I'm not out to make my car over into some modded race machine; I simply noticed the stock hose was a bit scruffy and ragged looking when under the hood. Wouldn't do to have the hose that delivers hot air from the turbo to the intercooler to split... and why pay over $100 for the cheap plastic and rubber OEM hoses when a similar outlay gets something much more temperature-resistant and with improved airflow (read: more horsepower)?  More on this next weekend when I should have the parts on hand.  (Way) further down the road will be disassembly of the intake manifold, as I need to pull it to get at the source of a minor fuel leak (again noticeable only on freezing-cold mornings like the power steering issue was), which most likely lies in the lines supplying the injectors or in the injector O-rings given everything else I've checked.

Obvious disclaimers: I can't be responsible for any damage you do to your car or yourself or others if you work on your own car. I simply want to share the simple process which worked for me! Be safe, and do your homework before attempting any maintenance on your vehicle.