Diff. between P/S & ATF ?

[2KBMW]

My BMW specifies ATF on P/S cap. I called the dealership
and they verified it to use dexron III ATF in the power
steering. I want to siphon out the fluid in the reservoir
and replace with clean fluid. I like to know the difference
between ATF & P/S fluid and why one would req. ATF over the
other. Also, what should I use ? I was thinking going
with the Valvoline Maxlife Dex/Merc.

 

[Titan]

Subaru P/S and ATF used to be the same, with the latest 5e transmission, they started with a fluid that no longer has PS stamped on it. In many cases, the main difference is the label on the bottle. But, I don't know squat about BMW's...

 

[INDYMAC]

The answer I got from a tech recently was that ATF handles heat better and doesn't gum up as much. I just did a PS flush and put Valvoline MaxLife DEX/Merc ATF in. It's too early to evaluate yet though.

 

[Titan]

That's what I do, too. As I mentioned, with the changed Subaru recommended fluids, I use the ATF in the PS, partly so I don't have to buy two types of fluid, partly because I think the ATF is more robust.

 

[artificialist]

ATF may contain a different set of additives that are more suited to the materials in your power steering system.

In any case, if it says to use ATF, use ATF.

I have used full synthetic Mobil 1 ATF (Mercon V) in power steering systems with really good results.

 

[mechtech2]

Not much difference.
I'd use ATF for sure in your car.

 

[mechtech2]

One more thing - Honda's often have special PS fluid, and ONLY that should be used in their systems, with no mixing.

 

[Hammer]

Quote:

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My BMW specifies ATF on P/S cap. ....... Also, what should I use ? I was thinking going
with the Valvoline Maxlife Dex/Merc.

---

I use the Maxlife ATF in my BMW and it works well and stays red. It also seemed to slow down the seepage at the Power steering cooler hose connections.

Hammer

 

[Jett Rink]

Hammer,
I have this problem, too. I leak power steering fluid at that hose connection where it connects to the rack on the passenger side.

I've been using a Castrol ATF, adding about one ounce per week or so. But it seems to be leaking a little more lately. I might give this Maxlife ATF a try.

 

[benjamming]

What causes it to develop a leak at the P/S hose connections?

 

[02zx9r]

Quote:

---

One more thing - Honda's often have special PS fluid, and ONLY that should be used in their systems, with no mixing.

---

why do hondas have to use only honda fluid? My g/f has an 06 acura rsx type s, if she ever lets me do I have to use honda only ps or atf in it?

 

[widman]

You can frequently fix leaks in the pump seals and hoses with automatic transmission sealer/conditioners.

I use ATF in all power steering systems. There is no PS fluid in the whole country. Not even dealers.

 

[Jett Rink]

benjamming: i haven't taken any parts off there, but I have identified that spot as a leak. I suspect it is just an aging seal. From the looks of the fluid when I got it, the previous owner never changed the fluid in the power steering. I did the turkey baster method several times and now the fluid looks good. It has just gradually developed a leak at that point.

widman: is there any particular automatic transmission conditioner / sealer you have used (or seen used) with success in a power steering system? i thoght something like Valvoline Maxlife ATF with Stop Leak
http://www.valvoline.com/pages/products/product_detail.asp?product=73

might improve things a little. It is only a few dollars for a quart, so what do I have to lose, right? If it would just slow the leak down, I'd be satisfied.

 

[benjamming]

You can try ARX as it can work with power steering units as well.

 

[wgtoys]

"why do hondas have to use only honda fluid? My g/f has an 06 acura rsx type s, if she ever lets me do I have to use honda only ps"

The why I don't know, but Honda specific PS fluid is what you would need. You can even buy special fluid at our local NAPA which is labeled Power Steering Fluid for Hondas and Acuras.