Philes’ Forum – Summer 2017


By Vic Lucariello, Sr.

Hello bimmerphiles! In this sojourn into the Philes’ Forum chronicles, I have a follow up to my last column together with a new item on brake fluid.

Last time out, in the Spring 2017 Bulletin, I wrote about using Dexron III-type automatic-transmission fluid [ATF] vs Pentosin CHF 11.S fluid in your Bimmer’s power steering. [You should be able to download the Spring 2017 Bulletin from the NJ Chapter Website.] I advised that, if your Bimmer uses Dexron fluid, you should not change the system over to CH 11.S or mix the fluids. Since I wrote that, additional information has been forthcoming.

After reading the Spring 2017 Philes’, bimmerphile Sal Puleio, inveterate owner of Rennsport Motor Works in Hackensack, contacted me and sent a copy of a BMW service information bulletin, or SIB. [In the auto-repair industry, these bulletins are generically known as TSBs, but BMW has their own name for them.] The SIB in question does corroborate what I had previously written [and what was confirmed by Matt Kimple at Bridgewater BMW], “The mixing of CHF and……ATF is NOT permitted [emphasis mine]”.

However, the SIB goes on to state that if a power-steering system is to be converted from Dexron III to Pentosin CH 11.S, “….the system must be drained as completely as possible.”

Sal and I discussed this, and we concur in recommending that if a power-steering system is to receive a fluid conversion, simply draining the system “completely” is not the best way to go. We recommend that the system be drained [hoses disconnected] then filled with the new fluid [Ah…hoses reconnected], then the vehicle started and warmed up, with the steering moved from lock-tolock [fully right, then fully left] a number of times. Then drain the system again and refill with the new fluid after changing the fluid reservoir.

Why would you want to change your steering-fluid type? Glad you asked. In specific cases, such as certain E46s [3- Series in production from 1998 – 2006] with powersteering noise under certain operating conditions, it may be beneficial to convert from the original Dexron III to Pentosin CH 11.S. According to several sources, CH 11.S has about half the viscosity [measured at 40-degrees C (about 104F)] of Dexron III. Viscosity can be roughly defined as resistance to flow. However, converting an old system to a less-viscous fluid may foment leakage, so be advised of this as well. If you effect such a conversion, the new reservoir will probably already be marked indicating that CH 11.S should be used. If it is not marked, be sure to source or make a label for it.

Much thanks to Sal for taking the time to look up and send me the SIB and for consulting with me on this topic. Rennsport is located on Berlews Court in Hackensack [201- 489-5577]. Sal has been taking care of NJ-Chaptermember Bimmers since 1981, and he has professionalautomobile- technician experience preceding that. Legend has it that Sal advised Henry Ford on the type of transmission to use in the Model T [or was that Henry Ford II and the Edsel?], but that, folks, was before my time.

While we are on the subject of fluids, here is an update on my continued testing of brake-fluid boiling points. In commissioning my new shop here in CO, I finally unearthed the Chapter’s brake-fluid tester.

For those who do not remember my previous articles on the subject, the DOT 3 and DOT 4 brake fluids found in most vehicles today [including the DOT 4 low-viscosity fluid in recent Bimmers] are hygroscopic, meaning that they have an affinity for moisture. Atmospheric moisture gains access to the brake fluid via the master-cylinder-cap vent, the seals on the caliper pistons, and, some say, via osmosis through the brake hoses. The effect of this moisture is twofold: it foments corrosion of the brakesystem components and it reduces the boiling point of the brake fluid. Since brakes get hot in operation, if this heat causes the brake fluid to boil, partial or complete loss of braking will occur. BMW and some other manufacturers recommend periodic replacement of brake fluid, while some other manufacturers inexplicably do not.

It has been my conclusion, particularly after observing vehicles being driven by driving-illiterate folks negotiate the approximately 8-mile descent of Wolf Creek Pass [they drag their brakes almost continuously as opposed to using them as briefly as possible and then letting them cool between applications] that it is pretty hard to boil your brake fluid on the street, even if you try like these folks are doing. [Of course it is a different story on the track.]

An example of this hit [too] close to home when my daughter visited last month. [Thankfully, she does know how to use her brakes properly.] While she was here, I renewed the front-disc-brake pads in her ’01 Jeep Cherokee, and in doing so took brake-fluid samples from both front calipers. The boiling point of this unknown-age fluid tested at only 370 F! Typical parts-store DOT 3 brake fluid tests at maybe 500 F out of the can, while premium DOT 4 fluids like Ate Type 200 test at around 570 F. Some of the boutique [read: expensive] fluids purport boiling points of 600 F or more, but that is fodder for a future Philes’ Forum. The Cherokee has negotiated Wolf Creek Pass a number of times with this brake fluid [see Photo #1], so my conclusion seems justified. After checking Amy’s brake fluid, I asked her how her brakes had felt coming through Wolf Creek Pass. She said they were fine.

Photo #1 – Can This Be MY Daughter’s Brake Fluid?

That’s all for now, bimmerphiles. See you next time. Anyone wishing to contribute to Philes’ Forum can contact me at I’m interested in tech tips, repair /maintenance questions, repair horror stories, emissions-inspection sagas, product evaluations, etc.

© 2017; V.M. Lucariello, P.E.

Philes’ Forum – Spring 2017


Trip Lee (1947 – 2017) – New Jersey Chapter Icon

The New Jersey Chapter, as well as humanity, suffered a great loss when Trip Lee passed away on 14 February. Trip was a unique, consummate gentleman of intellect and character, and I feel privileged to have known him for more than 30 years. If you are thinking I greatly respected and admired Trip, you are correct.

While some gearheads tend to be one-dimensional, Trip had varied interests, including history and aviation, in addition to his love of all things mechanical. One time he told me that as part of his study of the U.S. Civil War, he was reading soldiers’ letters written during the conflict. That’s some pretty serious study if ya ask me.

Trip and I would occasionally recommend books to each other. Our most recent correspondence, late in 2016, concerned a book about the closing months of WWII and how British airmen, at great cost, helped ameliorate the swarm of Kamikazes over the waters near Japan. The Brits did this by attacking Kamikaze airfields.

I can neither count nor recall all the times Trip helped me out, whether it was instructing novice-driver me at Lime Rock, mentoring me when I aspired to become a driver-school instructor, tactfully advising me when I became Chief-of-Tech for our driver schools, giving me lathe-operation pointers, or finding cool gearhead stuff for me or us. He once found a source in Germany and had imported two “dogleg” or “close-ratio” 5- speed transmissions, one for wife Judy’s M3 and one for mine. Trip found me a very nice, industrial-quality, [made in U.S.A., no less] floor-mount drill press that I use in my shop nearly every day. When Trip upgraded his TIG welder, I got his old one. One time he gave me a completely functional, 12” Clausing turret lathe.

I could continue, but knowing Trip, he would say, “Enough already; let’s get to the good stuff”. [But Trip would phrase it tactfully.] So Trip, if you are reading this, thanks, man.

The good stuff this month concerns BMW power-steering reservoirs. I looked in the Philes’ Forum archives, and the best I can tell I have not written on this subject in more than 10 years.

In January 2007 I was writing about oil filters, and I wrote that in addition to the oil filter, air filter, fuel filter, and cabin filter, your Bimmer also has a power-steering filter. This filter is located in the bottom of the powersteering- fluid reservoir, and unfortunately, unless your Bimmer is 40 or so years old, the filter is not replaceable without changing the reservoir.

Photo #1 depicts the power-steering reservoir found on many Bimmers from model year 1982 right up to much later models, such as the E84 X1 and E87 1-Series. Photo #2 shows a reservoir cut in half to reveal the internal filter. I think it a good idea to change the reservoir/filter whenever you do maintenance on the power-steering system such as changing the fluid, hoses, pump, or steering box. While you’re at it [actually, before you install any new parts], it’s also a good idea to flush out the system. The January 2007 Philes’ Forum [available on the NJ Chapter Website], describes one procedure for flushing the power-steering fluid.

Photo #1 – Ubiquitous Power Steering Reservoir
Photo #2 – Power Steering Filter Revealed

Driver-school Padrone Jeff White emailed me about his 2000 528i E39 5-Series touring [manual trans!]. Jeff is replacing the power-steering reservoir, and the replacement-reservoir’s cap indicates that Pentosin CHF 11.S fluid is required, and Jeff has been using Dexron-type automatictransmission fluid [ATF] as specified in his owner manual. Jeff was told by the aftermarket supplier of the new reservoir that Jeff needed to convert the system to CHF 11.S fluid, and Jeff questioned me on how to do this.

The current BMW part number for Jeff’s power-steering reservoir is 32 41 6 851 217. The only apparent difference between the current version and superseded versions [eg: 32 41 1 097 164] is that the cap on the current version specifies CHF 11.S fluid, not ATF. See Photo #3 [Courtesy of Jeff White].

Photo #3 – Cap From Current Replacement Reservoir
Photo by Jeff White

My response to Jeff is that the steering-system design, not the reservoir, is what determines which fluid is to be used, and that he should continue to use ATF in the E39’s power steering. Just to double-check, I contacted Matt Kimple, service manager at Bridgewater BMW, and he confirmed that IF YOUR BIMMER ORIGINALLY USED ATF IN ITS POWER-STEERING, DO NOT PUT CHF 11.S IN IT, REGARDLESS OF WHAT THE RESERVOIR CAP INDICATES. If you are in doubt about which fluid to use, call Bridgewater’s parts department [888-579-0048] with you VIN and they will supply the correct fluid. Pentosin CHF 11.S fluid is greenish in color while ATF is reddish. Old yucky ATF can be a reddish-brownish.

Further investigation suggests that when BMW switched to CHF 11.S steering fluid on most models beginning circa the E60 5- Series, they changed the fluid-reservoir cap such that it indicates that CHF 11.S is required. But what if you, like Jeff, need a reservoir for an older model? BMW thought of this as well, and provides a label indicating that ATF should be used.

The part number of this label for Jeff’s E39 is 71-24-6-798-132. Or you can make your own label like Jeff did. That’s what I would do. So too would Trip.

That’s all for now, bimmerphiles. See you next time.

Anyone wishing to contribute to Philes’ Forum can contact me at I’m interested in tech tips, repair / maintenance questions, repair horror stories, emissionsinspection sagas, product evaluations, etc.

© 2017; V.M. Lucariello, P.E.

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