[Mik325tds]

I'm wondering if the previous owner of my car changed the steering fluid reservoir already and now filled it with ATF. Does your 335d also have "ATF Only" printed on the reservoir? Mine is a 2011.
I just changed the fluid and it was murky brown. So it was hard to tell if it was ATF or a mix between ATF and CHF.
In any case, would anyone recommend changing to CHF? I hear that ATF is rough on the seals and at least in my car it is always leaking out of the reservoir. But I also read that CHF and ATF shouldn't be mixed, so a good flush would be required at least.

[Tambohamilton]

Ask the dealer, is the only way I know for sure...

From my own research, I think the seals should be fine with either ATF or chf, but I could be way wrong there. Still wouldn't recommend mixing fluids, of course.

Mine is a UK 2007 330d without active steering etc, and wants ATF according to BMW.

[apexit4]

If I'm not mistaken, progressive steering equipped cars were ATF only. Everything else used CHF. I was also led to believe its not a good idea to mix the two.

[Mik325tds]

Originally Posted by apexit4

If I'm not mistaken, progressive steering equipped cars were ATF only. Everything else used CHF. I was also led to believe its not a good idea to mix the two.

From what I'm reading, it's the other way around. All cars that have other hydraulic systems like adaptive steering or suspension height control use CHF. All others ATF.
Can you guys with the US 335d please take a look at your steering fluid reservoir and report back?
I know mixing the two fluids isn't a good idea. My question was if ATF could be flushed out by feeding CHF into the pump while letting it drain out the return line until fresh fluid is visible. Obviously, this would have to be done while turning the steering wheel lock to lock. Would the remaining mix still be detrimental?

[335dlci]

I have nevee seen anythin else other than atf in my 15 years of working on bmws on diesels.

[apexit4]

Originally Posted by Mik325tds

From what I'm reading, it's the other way around. All cars that have other hydraulic systems like adaptive steering or suspension height control use CHF. All others ATF.
Can you guys with the US 335d please take a look at your steering fluid reservoir and report back?
I know mixing the two fluids isn't a good idea. My question was if ATF could be flushed out by feeding CHF into the pump while letting it drain out the return line until fresh fluid is visible. Obviously, this would have to be done while turning the steering wheel lock to lock. Would the remaining mix still be detrimental?

Its possible I had the two mixed up. Its been about two years since I last had to refill the power steering system, so my memory is hazy. I dont have adaptive steering, so I dont think anything will be written on my power steering cap. I replaced the O ring on it a few weeks back and dont recall seeing any writing on it.

[Tambohamilton]

Originally Posted by Mik325tds

From what I'm reading, it's the other way around. All cars that have other hydraulic systems like adaptive steering or suspension height control use CHF. All others ATF.
Can you guys with the US 335d please take a look at your steering fluid reservoir and report back?
I know mixing the two fluids isn't a good idea. My question was if ATF could be flushed out by feeding CHF into the pump while letting it drain out the return line until fresh fluid is visible. Obviously, this would have to be done while turning the steering wheel lock to lock. Would the remaining mix still be detrimental?

I think you're right about the CHF - that stuff is definitely used for active steering and suspension.

Mine has had a weak concentration of CHF in it for over a year, as I got the wrong fluid initially...I think no detrimental effects so far, though my PAS pump is tired (was before I changed the fluid too).

[Yozh]

335d - ATF
X5d - CHF

[Mik325tds]

Originally Posted by Yozh

335d - ATF
X5d - CHF

Thanks Yozh, that was what I was looking for.

[Asonchadwick]

Well I dunno what's wrong with my car. I pulled some old fluid out of my 335d, took it to the dealer, they said it was chf11 not atf. I never saw any red fluid and nothing in the cap. Flushed out all the fluid into a bucket it was dark but not red. What's the deal?

[Tambohamilton]

Does it have active steering? If so, probably CHF11S. If it's just running HPAS, it's ATF...probably. Just ask the dealer for the spec for your car; ignore the fluid that's in it.

[335dlci]

Originally Posted by Tambohamilton

Does it have active steering? If so, probably CHF11S. If it's just running HPAS, it's ATF...probably. Just ask the dealer for the spec for your car; ignore the fluid that's in it.

No. Afs was not available.

[Tambohamilton]

ATF it is then, right?

[robnitro]

Edit: supposedly cannot mix BMW ps chf with atf. But there is nothing conclusive.

Even in other cars the power steering specific fluids like chf are a higher quality than atf and can replace atf.
If you're in doubt just use chf. There are model years where it went from atf to chf with no changes in part numbers etc. Chf is probably a synthetic that lasts longer so they did this for their "lifetime" warranty claim, like they did with the transmission.

[Mik325tds]

Originally Posted by robnitro

Even in other cars the power steering specific fluids like chf are a higher quality than atf and can replace atf.
If you're in doubt just use chf. There are model years where it went from atf to chf with no changes in part numbers etc. Chf is probably a synthetic that lasts longer so they did this for their "lifetime" warranty claim, like they did with the transmission.

Ah, well this is interesting. I was just wondering because these warnings "never mix ATF and CHF". How meticulous does one need to be when changing from ATF to CHF? Would it be sufficient to take the hoses off the reservoir, fill CHF in the one that goes to the pump and catch the fluid on the return while turning the steering wheel and operating the pump with a drill?

[robnitro]

Originally Posted by Mik325tds

Ah, well this is interesting. I was just wondering because these warnings "never mix ATF and CHF". How meticulous does one need to be when changing from ATF to CHF? Would it be sufficient to take the hoses off the reservoir, fill CHF in the one that goes to the pump and catch the fluid on the return while turning the steering wheel and operating the pump with a drill?

Oops, you are correct. My fault.
odels that you can swap both oils without any problem include:

Ford
GM models
Models that it is unsafe to swap power steering fluid and transmission fluid includes:

Mercedes Benz
BMW
Honda
Audi

[RED-d]

My 2010 says ATF on the cap. Also, don't forget the PS reservoir has a built in filter (kind of like the trans pan). Might be good to replace that when refreshing your fluid.

[Enzo335d]

I changed my power steering fluid recently and also have a '11. Mine used ATF fluid.

[daniel35d]

My '09 335d E91 without active steering takes CHF 11S.

The reservoir says it, and has a green sticker.

When I check RealOEM it also says CHF 11S.



Maybe colder climates use CHF instead of ATF? I live in Norway and the car was sold new here.

[Asonchadwick]

Bimmercat definitely says chf for 335d

[335dlci]

Originally Posted by Asonchadwick

Bimmercat definitely says chf for 335d

Who is bimmercat? Sounds like an YouTuber

[Tambohamilton]

Bimmercat is like realoem, but a bit more user friendly