Power steering fluid

Great Legacy info in this forum and I might have a prose problem. I have a 2012 2.5i premium Legacy. I tried the Valvoline Maxlife synthetic in a red container but it might have damaged my pump. Has anyone else had this experience? Read on the a narrative of power steering flushes gone wrong.

 

I recently did the cvt fluid drain and refill method twice with Valvoline cvt fluid. Going downhill I feel there is less resistance so I'm happy with the fluid. I had an extra quart of the fluid and flushed the power steering system.

 

I read that several people use the valvoline maxlife atf red bottle as well as Mobil 1 synthetic atf. The reservoir cap and owner's manual suggest a dex fluid or idemitsu fluid. I figured the valvoline cvt is an idemitsu equivalent and gave it a shot.

 

I pulled the return line to empty into a milk jug. I used a bottle pump to suck out the reservoir fluid. I removed the serpentine belt and jacked up the car. After the reservoir was filled with new valvoline cvt fluid, I spun the power steering pulley by hand. I kept the reservoir filled and it eventually changed color on the return end. Then I turned the steering wheel lock to lock while keeping the reservior full until I was almost out of fluid. Put the return line back on and everything was great.

 

I drove the car about 200 miles and noticed the engine seemed quieter and the steering felt smooth. The steering before the flush always felt tough like well done steak. But I did wonder if I had done something wrong by using the cvt fluid. The old fluid was a reddish brown like old dex/mercon fluid. I thought I better use a dex fluid.

 

I did the same procedure with the valvoline max life atf red bottle. I hand spun the power steering pulley, went lock to lock, and the fluid changed from amber to pink. I started the car and the power steering pump instantly started groaning. I let the fluid warm up while checking the reservoir level. The fluid seemed to be foamy like the groans were aspirating the dex fluid.

 

This sound caused me to panic and the panic continued through six hundred feet of driving. I back out of my driveway and basically did a U turn back to the drive way. The steering was jittery and notched. The pump whinned and groaned even if it was just at idle.

 

I drove to the nearest source of Valvoline CVT fluid and did a 1qt flush in the parking lot. Drove home and did another 1 qt flush. Returning to this fluid made major improvements in reducing the pump noises and notched feeling. It didn't eliminate them.

 

After more thought I decided either the viscosity of the Maxlife atf dex/merc fluid was never good for the power steering fluid or the cvt fluid when mixed with maxlife had a chemical reaction and at this point I've damaged my pump.

 

I thought about flushing with another quart of cvt but the system fluid had been amber after 30mi of driving. I was still getting a little groan at startup and whine when it was warm. I thought I'd use an atf supplament and see if there's a chemical fix.

 

I initially wanted to try LubeGuard atf supplament platinum, frictiin modifier, or basic but the 12 ounce volume seemed excessive for a .8 quart system. I used the handpump to drain the reservoir and I added LubeGuard's power steering protectant.

 

At first the pump groaned again like it was MaxLife in it again and I thought this was heading toward a breakdown. The noises went away and the notched feeling smoothed. The system seems better but not as good as the initial flush with cvt fluid.

Welcome to the 5th gen forums!

 

Sorry to hear about the power steering problems.

 

First off, I believe the CVT fluid is made by Mitasu. The Idemitsu fluid mentioned on the PS reservoir cap is Idemitsu ATF HP, IMO, not the CVT fluid.

 

I have seen more than a few people say they have used various synthetic multi-vehicle ATF in their PS systems. I myself flushed with Redline with no problems thankfully.

 

I dont know the makeup of CVT fluid and I dont know why it seems to work better in your system, but as I understand the PS is specced for Dex or ATF HP.

On a 5th gen the PS fluid should meet Dexron III ATF spec....

which means Dexron VI ATF is also fair game (and actually better).

 

We wrote about this perhaps 6 years ago.

 

Multiple places and threads on the forum discuss PS fluid flushes, drain n fills, fluids used.

Edited October 3, 2018 by Perscitus

I would put the ATF back in the vehicle and follow the factory fill and bleed procedure for power steering. I doubt that you messed it up.

 

Mine sound horrible for a week and I kept bubbling up and overflowing the power steering reservoir. I thought I had gotten air and system and wasn't properly bleed it or some how ruin my PS pump. I had forgotten the hose clamps on the PS, when I had removed it for the timing belt. The GT engine covers hides the power steering pump.

groaning typically means air in system.

 

Use the Valvoline synthetic atf that meets specs. it will flow better in colder weather

The groans have mostly disappeared except a little whine with initial startup of the day. The notched feeling going back and forth about 30 degrees from center is better but not gone. I'll give the dex iv fluid a shot if this cvt fluid has poor cold temp response. Thanks for the responses.

Subaru specs Dexron III or equivalent (traditional) ATF fluid for the Power Steering system. CVT fluid is completely different than ATF fluid. GET THE CVT FLUID OUT OF THERE IMMEDIATELY!!!!! Hopefully you have not damaged the power steering pump and rack.

Are you all going to think I've gone mad?

 

My car is a UK 2012 Legacy ... And it's got electric power steering, was this UK only then?

Are you all going to think I've gone mad?

 

My car is a UK 2012 Legacy ... And it's got electric power steering, was this UK only then?

 

We didn't get the diesel motor in the US.

Are you all going to think I've gone mad? My car is a UK 2012 Legacy ... And it's got electric power steering, was this UK only then?

Not UK-only.... more of a whole-world EXCEPT North America (US/CAN).

We have hydraulic PS over here. I think Oz has them too.

We have hydraulic PS over here. I think Oz has them too.

 

I'd prefer hydraulic, it was a right surprise the day my steering light came on after going through a big puddle!

 

When I got under it and took the motor off the rack, it was full of water (that obviously poured out straight into my eye)

^ that should not happen, is a seal compromised ?

A UK puddle is bigger than a US puddle.

 

Yeah the less electrics the better IMO. Although Subaru PS pumps have their own share of problems from what Ive read. Heck, mine had a pump replacement at the dealer at only 35k kms shortly before I got it.

^ that should not happen, is a seal compromised ?

 

It didn't appear to be, I'm thinking hot car, cold water may have drawn it in by some weird physics stuff.

This puddle was probably halfway up my wheels.

I used to drive a Land Rover and forgot I was in a car now

We have hydraulic PS over here. I think Oz has them too.

Can confirm, have hydraulic PS down here.

I replaced the Valvoline CVT fluid in the power steering system with Valvoline Dex VI synthetic. I noticed about a 2-5 mpg gain going to the Dex VI. Unfortunately there are too many things that could have influenced the specifics of the result but there was an undeniable increase in MPG after removing the CVT fluid from the power steering system. The product spec sheets do indicate viscosity at 100 C to be 7.2 for the CVT and 6.0 for the DexVI. Besides mpg, the fluid change did change the pump operating sound and steering feel to be slightly less responsive but with less drag.

 

I recently changed my girlfriend's 2011 Subaru Legacy PS fluid with Eneos Eco ATF which is DexIII compatible and fully synthetic. Similar results with the steering feeling smoother and less drag but slightly less responsive. At this age with the vehicles the steering linkages could also have some slack so I don't think it's all to do solely with the fluid.

 

I liked the CVT fluid characteristics the best. I couldn't hear the PS pump spooling and the steering felt more responsive, but it did negatively impact MPG. The DEX-VI fluid did flow much better while I was in Iowa when it hit zero degrees. Maybe there's a perfect fluid with the attributes of improving MPG and having a connected steering feeling. Someday I'll find it.

US spec'd legacies did not get the electric power steering until 15 model year. personally not a big fan due to lack of feedback....

I have replaced the fluid again. After using Eneos eco ATF in my girlfriends 2011 2.5i Legacy I would say that has been the easiest option. I work for a company that replaces hydraulic lines on construction equipment. I routinely have left over 46 weight hydraulic fluid from jobs and decided to try it out.

 

At work we fill fluids like for like and the main considerations are if the tank lists zinc free, if the fluid is ATF (red), universal tractor fluid, or very rarely it might be motor oil. I haven't seen any equipment use brake fluid systems. I also have access to Aeroshell 46 which is a mineral base and highest quality fluid for aeronautical applications. It's similar to Pentosin CHF 202. Pentosin CHF 11s is lighter weight and fully synthetic so similar to Aeroshell 32, which I don't have on hand.

 

I drained the Dex IV and flushed with 46w hydraulic fluid. I put about a gallon through the system before the fluid was clear. After driving a couple months with this fluid I wouldn't recommend the swap unless steering effort is major consideration. Compared to the Eneos Eco Atf, I'd say there isn't much difference in steering behavior and feel. Between the Dex IV and Hyd 46 I'd say the Hyd 46 reduces steering resistance and makes the feel much lighter. The Hyd 46 is probably a higher viscosity than Dex IV. The Hyd 46 will have the same anti-wear additives but none of the friction modifiers for clutch pacs to engage. Friction modifiers are an undesirable component for a hydraulic fluid but overall isn't going to make a big difference in fluid characteristics for the small power steering system. If it means having a fluid specifically for the small power steering system, it's not worth the space to keep a separate fluid. ATF is a fine fluid and most people might not notice and change from ATF to straight hydraulic fluid.

 

I haven't noticed a difference in fuel economy between the Hyd 46 and Dex IV. It's been relatively cool in the bay area so I can't comment on hot weather performance. If you're inclined to try different fluids in the power steering system I'd recommend the Eneos Eco ATF plus. Next on my list is to try Pentosin CHF 202 when I go to replace the power steering lines. I haven't decided if I want to fabricate my own or just order replacements.

Pentosin says CHF fluids aren’t compatible with ATF type fluids. How will you purge the whole system of the old stuff before you put it in when you try that? Who knows what the interaction might be.

 

 

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Swapping from one fluid to the next is fairly simple. I remove the return line going to the reservoir and put the end into a clear container like a gallon milk jug. I unmount the reservoir and support it so I can see it from the driver's seat and so it is the highest point in the system.

 

Without turning on the car I raise the front of the car so the wheels are off the ground. I turn the steering wheel lock to lock. I watch the reservoir level and refill as needed. I stop doing this when the fluid exiting the return line into the clear container is consistently new fluid.

 

Next step is to refill the reservoir and run the engine for about four seconds because the fluid from the reservoir is getting sucked in by the pump and exiting the return line. This is when I notice if the fluids are miscible. Sometimes the return line spits out froth. I refill the reservoir and repeat this about four or five times. When the fluid exiting looks consistently new fluid, I remount the reservoir and reattach the return line.

 

Last step is to let the engine idle and let the fluid circulate. It helps to turn the steering lock to lock. After about five minutes, most of the air bubbles should have circulated. Then the front can be lowered to the ground. Check the fluid level before driving and add as needed. Drive around for a bit. Check the level again and add as needed. It's best to check the system when it is warm/hot and the car is level.

 

The basic interaction between ATF and hydraulic fluid is the fluids foam. When switching between ATF fluids it takes about two quarts to adequately flush the system. When I switched to Hyd 46, I used about a gallon of fluid.

 

What I've noticed is that each fluid has a different steering feel. The effort required to change direction and input to maintain a straight line are different with each fluid.

 

Thus far I'd suggest Eneos Eco ATF Plus with the Lube Guard power steering protectant. This combination to me has improved the steering feel, reduced effort, and not adversely impacted miles per gallon.

That's pretty hardcore going through all that to see the difference between fluids. Thanks for sharing your experience!

Additional fluid update:

 

My last set of fluids was a standard 46w Hydraulic fluid and then Lube Guard Synthetic Power Steering Fluid which probably had some common additives like anti-wear and anti-foam. The steering feel was great. It felt responsive and light. I wasn't too keen about was the engine drag. At a standstill when turning the wheels left or right, the idle would surge as the power steering pump increased drag and the ecu would slightly overcompensate a reduction in idle speed. Otherwise the steering pump drag was unnoticeable.

 

I switched from 46w hyd fluid to LubeGuard Universal Power Steering Fluid. It was close to what I expected. It didn't behave much differently than the 46w hydraulic.

 

I've been wanting to try Pentosin CHF 202 or 11s. I've read Audi/Volvo forums complain about the fluid because it's a very thin fluid and rather expensive. I was curious about it because the viscosity index is incredible and is purely a hydraulic fluid. I found a place that had the 202 at a more reasonable price than I normally see and I bought a liter. I did the flush earlier today and things seem good.

 

The CHF 202 is a thinner weight fluid so the power in the steering doesn't feel as aggressive. This also means the viscosity drag is less. When I turn the steering wheel at a standstill the engine speed doesn't dip then pop up to compensate for the pump drag. We'll see how it behaves the next couple of weeks. If the fluid behaves well in the system then I'd recommend it for more challenging climates. If I still lived in Iowa, this fluid would help out with winter weather cold starts.

I’ve got an unopened bottle of CHF-202 in my garage left over from when I did the steering rack on my now dearly departed Audi. I think it’s a liter. It’s dark green and smells really weird! It’s just taking up space on my shelf. You can have it if we can figure out how to get it to you.

 

That said, as I’ve brought up in the past, Pentosin says the CHF stuff is not compatible with regular stuff. I’d worry what the combination of the old stuff and this new stuff might do. Further, I’d have real questions about the seals in the pump and the rack being incompatible with this stuff. I think they’re either nitrile or Viton, which is probably fine, but I don’t know for sure. Blowing a seal would be a ton of work for you. There even may be the possibility of degrading a hose and causing it to throw a bunch of trash into the pump and the rack you’d somehow have to clear out. Or, worse, you blow up the high pressure hose and shoot hydraulic fluid all over the place and ruin your pump completely.

 

I might be preaching to the choir, though. You seem pretty adventurous...

 

 

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