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Power Steering Fluid: CHF-11s or ATF

18K views 30 replies 13 participants last post by  LeverThis 
#1 ·
2 Dealers said according to a vin search CHF-11s is the correct fluid for my 1999 328i.

The majority of people online say all e46s use ATF. A handful say CHF is the correct fluid.

Is there a definitive answer on this?

Thanks
 
#2 ·
My 2004 325ci owner manual calls for atf dexron 3. I've been using mobil 1 ATF with good results. In fact, when I bought the car, one of the power steering lines had some sweat on it where it was crimped at the end. After flushing the system with new mobil 1 ATF, and then consistently flushing the reservoir every oil change, the entire power steering system is leak and sweat free.

I know my 1998 gti vr6 explicitly took chf11s and that was a zf steering rack. That chf11s is not cheap!
 
#3 ·
There are E46 cars manufactured with CHF-11S fluid and ATF.
Look your reservoir and cap.
For example my 2005 330i which is from warm climate, it uses ATF. There is text ATF only in reservoir cap.
My 2005 316i sedan which is for cold climate, uses CHF fluid. There is green sticker in reservoir cap (CHF-11S only).
 
#5 ·
It's been discussed recently. Your car takes ATF. Pentosin can be used with benefits of better flow in extreme cold.

Albeit if when it leaks, super difficult to clean. Sticks to everything it touches and is a magnet for anything that blows past it.
 
#6 ·
The Bentley manual (Steering and Wheel Alignment section, page 320-9) recommends ATF for the PS system. Don't rely on your cap unless you have had the car since new and know your cap has not been changed. Current ZF replacement reservoirs from ECS come with a cap that specifies CHF 11S (disregard the picture of the cap that specifies ATF). Replacement caps also come marked with CHF 11S. They sell an expensive BMW green sticker with "ATF Only". I just replaced the reservoir along with all PS hoses on my Z3 and am having to contend with the ZF reservoir with a cap that specifies CHF 11S when my car uses ATF. Actually the reservoir I got from ECS is a genuine BMW (ZF) reservoir with the BMW logo abraded off.

https://www.ecstuning.com/b-zf-parts/power-steering-reservoir/32411097164~zf/

https://www.ecstuning.com/b-genuine-bmw-parts/power-steering-reservoir/32416851217/

https://www.ecstuning.com/b-genuine-bmw-parts/power-steering-reservoir-cap-label/71246798132/
 
#9 ·
Im going with CHF. Did one last check at autozone and their system said ATF unless the car has certain hydraulic features, in which case it uses CHF. Vin # says CHF, so I'm assuming mine has those features.

On another note, is there a difference between a red and white capped CHF can?
 
#10 ·
There's no features. Your car doesn't have self leveling and/or Hydroboost.

I was with the dealers when BMW started to introduce hydraulic self leveling onto some of their cars. By means of either an electric pump in the trunk under the spare and morphing over to a two stage power steering pump.

Same cars, with self leveling, CHF. No self leveling, ATF. They're both hydraulic fluid BTW.

CHF comes in two varieties. CHF 7.1 which is usually a white can and is mineral oil based.
CHF 11/S which is usually in a green can and synthetic.

ATF or CHF will BOTH work and likely shouldn't be mixed. So get a sample and be sure.
Place a few drops onto a clean plain white paper. What's the color?
Reddish-brown =ATF
Greenish-dark brown = CHF

CHF will also get sticky and gooey when dried. Hence why is't so nasty to remove once it leaks. However it has better flow capabilities in extreme cold.

To reiterate my last story about CHF; I once had a Mk2 Jetta GLi. At the time many of the VW/Audi product line was using CHF 7.1. My car didn't. A friend @ a VW shop convinced me to switch. After my first leak, I swapped out the reservoir and went back to ATF.
Cleans up better and is less than 1/2 the price.
FWIW I am NOT aware of any E46 running CHF for P/S fluid. Just the caps on the aftermarket switched the labels (for the newer cars of E60>) and the story stuck. (Intentional pun)
We do a decent amount of racks, pumps, hoses (along with new reservoir) around here. The only thing we fill with is ATF, regular or synthetic if the customer wants the upgrade...
 
#14 · (Edited)
I went thru this too. Every website I went to listed CHF fluid. When I drained it it definitely was not CHF. It was the same fluid that came out of the transmission - which was a Texaco Dexron III compatible fluid which is no longer produced. I strongly suspect BMW filled the power steering in an E46 with whatever fluid they filled the auto trans. From a manufacturing point it makes sense for the day.

One of the most frustrating things about a BMW is determining which fluids to use.

If you take your car to a dealer they are more than likely going to tell you the spec fluid is CHF11 - but they are going to completely flush the old fluid out because it is not compatible with CHF11 and is no longer produced. Then they are going to charge you a ridiculous price for the service.

So - here is the rub. CHF11 is not compatible with most ATF's used when these cars were built. In fact when you mix the two the result is a very corrosive fluid - which is why a dealer will insist on flushing your system. If you don't flush your system it won't blow up right away but long term you are going to have hoses leak, pumps fail etc.

For me - understanding hydraulic systems and that any fluid will work - even water in an emergency - I went with a conventional mineral oil based Dexron III compatible fluid. The fluid is inexpensive and has good lubricant properties. I flushed it twice to eliminate any concerns about compatibility/contamination. The pump is much quieter and the hoses don't weep.

I would suggest if you use CHF11 you flush the system completely.

YMMV. Cheers
 
#13 ·
A USA 1999 328i came from the factory with ATF and should use ATF.
Your owner manual states to use ATF.
As MrMCar suggested, use ATF.
See what is already in there to confirm it is ATF.
Most of the places you are looking up list CHF 11S, because BMW considers it to have superceded ATF.
In short, use ATF despite what you are hearing.
 
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#17 ·
What are the oldest cars that used CHF-11 from factory?
Starting a new troll post? (Just kidding) A great question BTW.

Quickly scanning the old file cabinet in the dark recesses of my brain, I come up with:
E34 540 with the self leveling suspension. Huge black metal reservoir (replaceable filter BTW!) and had a two stage P/S pump.
That is to say they added another section to the pump and now it has two rotors instead of one. (Think of an overstuffed sandwich)

The reservoir fed the pump in the normal way. The front half (normal part) fed the power steering box. Servotronic or not.
The back half had a hard line running to the rear shocks with a filter in the line that ran a circuitous route to supply the rear shocks if/when needed to raise up the back. The unused fluid was sent back to the reservoir.Tantamount to fuel supply systems of old before running losses.

That car was filled with CHF 7.1 and during the production CHF 11 came along.
The older E28/E24 M5/M6 came with the 1st. generation of self leveling. Albeit this was a stand alone system that had an electric pump/reservoir/electronics located under the spare tire in the trunk. Running CHF 7.1.

I have no proof, just good ol' mechanics intuition and think that since the changeover from 7.1-11 the synthetic will find a leak (it was going to happen anyway) sooner, owing to it's superior flow over that of the non-synthetic....

I have to believe BMW chose CHF for the medium owing to cold weather and not wanting to pop the sensitive seals for the rear shocks? The steering system is used to such high pressures.
 
#15 ·
Is there a definitive answer on this?
I am gonna stick with the CHF even tho most are saying ATF.
So, what is in there now? Whatever that is, is what you should use. Do you live in a cold climate by any chance?
Mixing chf and atf is probably asking for trouble.
 
#27 ·
I ran horse laxative from tractor supply in my 98 gti vr6 when the rack developed a leak. I kid you not. An old timer mechanic told me I could use it temporarily instead of chf11s. Ran it for a few months until I sourced the rack and the knowledge to replace it. The pump was just fine after running the mineral oil laxative.

Personally, I'd drain the system and run Mobil 1 ATF and call it a day. CHF11S is way too expensive per liter.
 
#31 ·
I finally found a reference I trust: a copy of the Factory Workshop Manual (from allcarmanuals.com) that lists Dexron III ATF for all models ("Fluid and Lubricant Specifications" page 020-3). My quest is over!!!
Completely understand the confusion and hesitancy to go against what 2 out 3 dealers told you. Glad you found the manual, it's basically what we were citing as "the Bentley" which is a publisher of auto service manuals.
Good perspective on what the dealers were saying here ... especially the 3rd one that confirmed with the service tech who knew the e46.

Now I need to do my best to flush as much of the CHF out of the system knowing it's not compatible with ATF. Unless...the CHF will not harm the PS system, in which case I'll simply leave it in.

Suggestions welcome...
At this point, whether you need to depends ... was there any mixing of old atf with new chf?

If the entire system was virgin (rack, pump, reservoir, hoses and cooling loop) and you know its 100% chf then I think there is no technical reason to switch now.

If there is a mix, then it's a question of flushing it completely. The cheapest Dex 3 atf (which is fine to use here) will cost less for a gallon than a quart of chf11.

So what was replaced & how much chf went through system?
 
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