power steering

[mpetroul]

Hello, I have an '89 535i... The power steering res is low and it looks like I have a bit of a leak from one of the hoses that go from it to the pump and to the rest of the system. As evidenced by the wet hose going to the pump. I just was wantingto know what kind of power steering fluid does everyone use? it says ATF on top. I justwanted to know what everyone thinks is the best, thank a lot. Mike

[5mall5nail5]

Dexron Mercon III or compatible

For the leak, is it hte low pressure hose? I've had low pressure hose leak on 3 bmws in my family. Replaced and all is well. www.autohausaz.com for the hose.

[bmw slangen]

In your case it is most probably, as 5mall5nail5 says, a Dexron III compatible fluid. Dexron III is a standard from GM but the expression Dexron III became misused over time which I think made GM to require all brands which mention Dexron III to be certified or similar. This is probably the reason why Castrol TQ Dexron III was suddenly renamed to Castrol TQ DIII Anyway, that's the oil I use to the tranny and power steering.

But to be safe - take a look on the colour of your current power steering fluid. See below why.

For the power steering (and suspension leveling - they use the same oil) you use either ATF or CHF (I'm not going to go into LHM/LHM+ and similar fluids here since I know too little about that). Is it red then it is ATF. Is it greenish/brownish then it is CHF. If the oil is really old and burnt and never replaced then it could be brownish/blackish and it could be either ATF or CHF.

You shall never ever mix ATF and CHF - the rubber seals will start leaking.

Cars exported to cold-climate countries were filled with CHF from factory. CHF oil is a syntethic oil which can handle lower temperatures better than mineral ATF oil. On these cars they put a green sticker on the resarvoar saying "CHF only" or similar on top of the text that said "ATF only". Now it is quite common that this sticker disappears during the like 15-20 years of use. And suddenly it states "ATF only" but when you in reality has CHF oil in your system.

It is also very common here in Sweden to import BMW cars from Germany. Now German cars are not cold-climate equipped and therefor filled with ATF. But most cars sold in Sweden are cold-climate equipped and therefor are filled with CHF. It is then quite common to import a car and replace the ATF oil with CHF. Then you have a car where it clearly says "ATF only" on the reservoair but it is actually filled with CHF.

There are two CHF oils, the CHF 7.1 and CHF 11S. You shall never ever mix these two either.

So as a summary
ATF <=> CHF 7.1
ATF <=> CHF 11S
CHF 7.1 <=> CHF11S

[nmp411]

^ Very informative. Thank you!

[bmw slangen]

Thanks, I was actually asking myself the very same question for just a few weeks ago.

So I concluded that I should use ATF in my 535i -89 based on
- my car was imported from Germany
- the fluid I had looked very red-ish colour
http://www.exx.se/objects/autopower/6062.jpg
http://www.exx.se/objects/autopower/6076.jpg
- it said "ATF OIL ONLY" on the reservoar
http://www.exx.se/objects/autopower/6052.jpg

[russiankid]

Autohaus is your friend for these hoses. Do not go to the dealer for the hose that goes to the pump itself from the reservoir. Its $90 from the dealer, $33 from Autohaus. I just ordered one for mine.