View Single Post
Old 04-15-2011, 05:26 PM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
Join Date: Mar 2008
Posts: 25,236
Mein Auto: 02 BMW 525i M54 auto 130K
Originally Posted by pleiades View Post
Bluebee, why did you opt to use a Dexron VI ATF, and what was the problem with the Redline product shown in the pic above?
Long ago, when I first filled my power steering fluid reservoir, I stopped at the auto parts store and asked them what I should use (yes, I know. Rookie mistake #1).

They told me to use the Redline PSF (which said "BMW" in the marketing blurbs on the back, btw); and, at about $15 a quart (IIRC), it was pricey, but I thought I was giving my bimmer the 'good stuff' (yup, price is meaningless when it comes to quality ... rookie mistake #2).

As you know, our bimmers take ATF, not PSF, and I called Redline tech support who told me that it 'should be ok' in the short term; but that was when I decided to write the one-page description of one paragraph for the dozen fluids to keep in our glovebox:
- BMW E39 fluid summary printout for your glovebox (1)

As for Dexron VI (introduced in 2005) versus Dexron III, the only difference, according to the Redline technical support, was in longer-term situations (I forget all the details, sorry, it was a long time ago) but, Dexron VI, he said, was fully compatible with Dexron III and, in fact, he told me that GM no longer licenses Dexron III.

Anyway, I confirmed the fact that GM no longer licenses Dexron III on the Internet (yea, you 'could' call that rookie mistake #3, trusting the Internet, but in this case, I believe it). Here's what Wikipedia says:
All DEXRON-III licenses expired at the end of 2006, and will not be renewed.
So, I'm not sure the legalities, but it could be that nobody can print Dexron III on their label anymore ... even if they are Dexron III compatible.

This article about the roll out of Dexron VI says ...
perform more consistently in extreme conditions; and that would degrade less over time. They achieved these improvements, officials said, by raising requirements for oxidative and shear stability, foam performance and protection against pitting.

GM claims that Dexron-VI delivers more than twice the durability and stability in friction tests than do existing fluids.
BTW, here are the references in the bestlinks, to date, for users looking to learn more about their power steering:
- How to clean the power steering fluid reservoir internal filter (1) & how to replace the cap o-ring (1) (2) & why you want to fix the power steering hose drip onto the alternator (1) (2) (3) & how to debug PSP power steering pump noises (1) (2) (3) or steering rack noises (1) & a nice power steering pump autopsy photo (1) & how to flush fix cloudy ATF fluid (1) (2) and what PS fluid to use (1) (2) & DIYs to replace the power steering hoses (1) (2) (3) (4) (5).

So this seems to be a good recommendation for E39 owners:
  • Every oil change, suction out about 8 ounces (250 ml) of the power steering fluid and replace with Dexron VI ATF
  • Every five years (or so), when you replace the two lower oil-filter stem o-rings, also remove the T20 Torx bolt holding down the circular screen filter in the bottom of the power steering fluid reservoir and flush with gasoline (off the vehicle!) to clean the screen
  • Likewise, also replace the o-ring in the power steering fluid reservoir cap at the time you replace the two lower o-rings in the oil filter stem

Last edited by bluebee; 04-15-2011 at 08:30 PM.
Reply With Quote