VAP

I've finalized the plan I'm going to follow.

The Pentosin 11S seems to have a number of people that believe we suffer premature failure rates and problematic leakage of PS-related components due to 11S thinness. Many believe the fluid far better suited to Arctic conditions rather than the actual climes we use it in. They contend it doesn't have the viscosity to properly protect the ferrous metal sliding/rotating and reciprocal parts of the pump it is supposed to protect once up to operating temperature or higher during summer months. That once hot it's film stength and thickness is compromised via heat, it's insufficient to coat/protect those moving parts from metal-to-metal contact within the pump or the rack. That it's more like using WD40 or 3-in-1 oils at high tempeature. Because of that the 11S would be creating/contributing to its own higher temps via friction and viscosity break-down. Those higher temps, if this is true would similarly take their toll on seals in the hydraulic system in the form of accelerated seal wear via seal internal drying, checking and cracking. And given it's lightweight is also more prone to larger fluid volume losses than a slightly heavier viscosity fluid from the same leak-point, ie; "you lose more WD40 volume out of a pressurized pinhole than 30Wt oil." There's also at least the perception that the reason 11S turns black is due to the high ferrous metal content suspended in and circulating with the oil from the previously mentioned wear of metal-to-metal contact in both the rack and pump. I've personally always thought that to be small micron rubber seal particulates suspended in the fluid but I'll tape a strong earth magnet to a wire and go fishing in my PS reservoir... see what I catch. If there is moderate ferrous content, coupled with an ineffective viscosity the wear-n-tear on metal parts increases exponentially!

The Plan;

Fisrt thing I'm going to do before swapping oils is take my infra red laser pointer thermometer and get some readings from my PS reservoir. It's thin-wall aluminum is an excellent conductor of heat and should provide a great indication of 11S temps in the reservoir. Once I have the 11S reservoir temps documented I'll proceed with the oil swap.

Before swapping oils I want to also test for compatibility of the fluids. My feeling is using equal parts of 11S and ATF they will blend immediately when mixed, wthout shaking, stirring or agitation of any kind. In fact I'm counting on this as one of my "confidences" in doing it. If that doesn't pan out then I'll do a flush prior to topping off.

Much of my research last night was on which ATF to use. I couldn't decide on my own so I made a 2-column "pros/cons" list and viscosity, weight and temperature range won out. I'm going with Mobil 1 in this test simply because it's the lightest/highest temp rating, with the best anti-wear specs of all ATF's I could get specs on and easier-to-find in a pinch situation than other synthetics. And in the event of catastrophic oil loss it can be mixed with any/all ATFs of Dexron I/II specs.

I won't do a repeat stop-leak treatment, relying instead on the inherent stop leak properties found in virtually ALL ATF's and PS fluids including M1. But inexplicably absent, or at least unmentioned in 11S.

Once converted to M1 I'll repeat the temp testing and record any differences. Then just drive and see what, if anything, happens over the next few months. If this holds up and is problem-free I'll repeat it with the new rack, pump and high pressure lines when I install them in May/June.

So tell me... what's the forum spread on this? Over the short term I'm going with "will run dramatically cooler with quiter oil pump and no other problems whatsoever for the next 2-3 months." Long term; "same-o same-o"

nothing

No problems or issues at all so far. The CQ went back to daily driver status a few weeks ago and has performed flawlessly since.

My B4 is still on a 11s diet, but will get M1'd this summer as well - the stuff is cheap and ubiquitous compared to any Pentosin fluid.

I brought this up on this forum a couple of times last year - nobody here seemed interested in a Pentosin replacement.

I am looking forward to reading your results.

Junker CQ

and I compared it against Pentosin. The only thing that prevents me from going over to Mobil 1 is the horror stories I hear about using anything but Pentosin. I'm thinking about trying Mobil1 & see what gets destroyed.

VAP

try anything else because all we hear is "you HAVE to use Pentosin" which in my mind is a baseless presumption and for the life of me I can find no earthly reason for that to be truth or fact. In fact years ago VAG did use ATFs and suddenly overnight everything went to Pentosin. But the REALLY funny thing is the rack, pump, lines and reservoirs kept their IDENTICAL part numbers after the Pentosin switch. NOTHING CHANGED as it relates to the parts! Well if part numbers didn't change why should we assume only "one" manufacturer's power steering fluid will work!?! That's just CRAZY!

Junker CQ

before saying that it is ok to use Mobil1. My 2cents.

VAP

quieter, smoother hydraulic system with less leakage and smaller leaks when/if they occur. And I think any before/after testing the PS pump with a mechanic's stethoscope will confirm the pump will be DRAMATICALLY quieter during operation. Just this hunch I have ;-)

VAP

among the forum at-large and doom & gloom theories to subside. Some will move quickly to this while others will hesitate, wait, procrastinate and drag their feet. And some will NEVER do it... basic human nature of car culture. But regardless of the time frame any individual takes for that, the oil conversion HAS to start somewhere or we can never move past the wide-spread perception that "you GOTTA use Pentosin or your car will melt!"

And there's several, even at AW that have been doing it for FAR longer than 2 years already without a single issue to-date. Also the BMW and Porsche Forums. I'm not pioneering this trail. I'm just jumping on a large number of coat-tails that have been doing this since the early-mid 90's. There's people that have done this for over 10 years using simple ATF before the advent of ATF synthetics. Just do a search. "The truth is out there." ;-)

nothing

I researched this thoroughly before switching. I am very comfortable with and confident in my decision. I predict the result will be same after 2 years as it has been after 6 months. By your logic, why not 5 years?

As I recall, you were one of the naysayers when I shared my plans last year. That pervasive scared attitude on this forum is one of the reasons I don't share my plans or findings around here much anymore.

Somebody has to try it first in order for it to become proven. I was far from the first on this one - I'd say it's been proven for some time now.

Junker CQ

Interesting.<ul><li><a href="http://www.mobiloil.com/USA-English/MotorOil/Other_Products/Mobil_1_Synthetic_ATF.aspx">http://www.mobiloil.com/USA-English/MotorOil/Other_Products/Mobil_1_Synthetic_ATF.aspx</a</li></ul>

Mcstiff

My drive in to work seemed quieter (discounting noise from a little air).

Not sure of the cost (this bottle was gratis).

"BG Universal Synthetic Power Steering Fluid is a revolutionary 100% synthetic formulation designed for use in all power steering systems and under all conditions. The extremely high viscosity index of this fluid means that it does not appreciably thin when hot nor thicken when cold. BG Universal Synthetic Power Steering Fluid handles sub-zero temperatures at which most fluids fail. Also recommended for automotive central hydraulic systems, shock absorbers, automatic leveling systems and hydraulic systems which operate under extreme temperature conditions or variations.
Part No. 334 64 oz. (1.89L) bottle"