Power steering flush *edit* with a twist

[LJRuddy]

This week, I am working on flushing the fluids in my new SHO. First up to bat is the power steering. Now, I know I have heard that you can use ATX fluid instead of regular power steering fluid. Is this true? Any down sides to using ATX fluid? The reason I ask is this... I have 6 quarts of Valvoline high mileage Mercon 3/Dextron fluid sitting in my basement doing nothing. I have noticed that on cold start ups (10 degrees and below) that P/S system groans when turning the wheel. The fluid id kinda dirty as well. Would I be okay with flushing the system with this fluid? Should I mix it 50/50 with actual P/S fluid as well?


EDIT: I just went outside to move the cars around... Pulled the SHO to the back of the house and the P/S was groaning (granted the fluid id dirty and its 2 degrees out...) Well, a few minutes later, I went to go grab some cough drops from the store. As I pulled out, I noticed a small red puddle of fluid on the driveway. I pop the hood and see that P/S fluid had ran out of the vent holes and poured down onto the driveway. I pulled the P/S cap off and noticed that the entire res. was full of foam... Uh oh... What does this mean?

 

[frosho]

I wonder if maybe a line froze or was blocked somehow and caused pressure to build inside the reservoir...

I don't know if that's even possible, but you said it was pretty cold out so I'm just throwing it out there.

 

[LJRuddy]

I wonder if maybe a line froze or was blocked somehow and caused pressure to build inside the reservoir...

I don't know if that's even possible, but you said it was pretty cold out so I'm just throwing it out there.

Thats what I am thinking. The P\S pump was always louder than normal but I just attributed that to the dirty fluid. I am gonna wait till it warms up a bit to start it up. I will then drive it into the garage and stick a space heater under the pump. After a bit, i will start the car up and let it idle for a bit... Maybe I can unfreeze it that way. I hate cold weather.



Also, Anyone wanna chime in on the origional question?

 

[Kens1992mtxSHO]

I have used Valvoline High Mileage dex/merc for my power steering without any ill symptoms. As a matter of fact, I flushed my PS again just 2 days ago.

 

[frosho]

Also, Anyone wanna chime in on the origional question?

Woops, forgot to mention that IIRC someone recently said that ATX fluid is actually specified for our power steering system. I ain't positive though.

 

[93rev2sev]

If I were you , I would buy some "bulk" ATF for the flush and use the good stuff for filling it and topping it off.

Oh the foam is probably from moisture in the lines. It sounds like a flush is in order...at least...

 

[crazy_canadian]

I've always used ATF into the power steering and so does the Garage I work at.

 

[Devin]

I have AMSOil ATF in mine, but my entire system was evacuated when I filled up, so I didn't have to flush.

Do you really think the ATF froze?

 

[LJRuddy]

I have AMSOil ATF in mine, but my entire system was evacuated when I filled up, so I didn't have to flush.

Do you really think the ATF froze?

The fluid that is in it now looks like chocolate milk with dirt added in. Im sure there is a good amount of moisture in it that froze up.

 

[Kens1992mtxSHO]

Definitely time for a flush

 

[gmorrell]

Long ago, i remember reading some speculation that the ATF additives that improve auto-transmission clutch function might cause some stickiness in the steering rack piston seals, but I've never seen anything definitive to prove or disprove this notion. ATF is probably just fine in a PS system.

Personally, I prefer Redline power steering fluid, I've been running it for many years in all four cars with no problems.

Sounds like your PS fluid has quite a lot of moisture contamination, you may want to drain the system, refill it with some cheap PS fluid, drive it around and get it nice and hot, then drain again and refill with the PS fluid you'd really like to run long term. Maybe put a piece of cardboard in front of the PS cooler and do a little highway trip so the fluid gets decently hot. Do you do a lot of short trip driving?

SHO PS pumps have an over-pressure relief valve that's been known to fire off when the car is started after sitting outside overnight in below Zero temperatures. It vents the over-pressure back to the inlet side of the pump, which would creep back to the PS reservoir and possibly make it look like its over-filled.

The trapped water wouldn't boil when it's in the high pressure parts of the PS system, but when it returned to the reservoir and atmospheric pressure, the water would flash boil, and foam up the PS fluid. This is just like the water in the engine cooling system - as long as it's under pressure, it's boiling point is above the boiling point of water at 1 Atmosphere, but the second you remove the radiator cap, the cooling system drops pressure and all the water flash-boils pretty much right now.

 

[1993MTXSHO]

yes, our cars specify atf in the ps, also atf is a great cleaning agent, so it usually keeps everything very clean, nothing should be sticky. Unless maybe when it gets really old and beat up it starts to get sludgy, but iv never know atf to turn to sludge like oil would

 

[LJRuddy]

Well I topped off the res with ATF and went to subway. There was zero groan from the system and zero leakage. Its crazy what 15 degree temp differences will do to a car. Im still going to flush this system out asap though.

 

[93rev2sev]

Gary,

To your point...

I agree that there is a tiny bit of stickyness when using ATF in the PS. I have recent PS experience that made me think just that...then your post...now I'm convinced.

I just replaced my rack/pump and lines...everything is brand spankin' new. I filled it up with ATF and was very pleased with my new PS system.

However...during long, sweeping curves where I have to keep the wheel cocked 20 or 30 degrees off center, I can feel the slightest little stickyness when making minute course adjustments(it's such a small amount of sticky, that I don't even care to experiment with changing to PSF). The first thing I thought was..."this is how it's SUPPOSED to feel" since it was all brand new. I'm sure it's from the friction additives in the ATF.

 

[hawkeye18]

I use ATF in both my cars' PS systems. Mobil 1 ATF, to be specific. It works great... keeps the whole system nice n clean. It got all sorts of crap out of the system. What you do is unplug the PS cooler down by the radiator and let it flush out of there. Then, you fill the system up with el crapo ATF... flush, repeat as desired, then plug the cooler back up and fill with desired ATF. I got an amazing out of gunk (seriously, snot chunks), metal shavings, etc. Now, 6500 miles later, the PS fluid is still decently red. Sure doesn't look like the oil that came out the first time!