Is it ok to replace CHF 7.1 with synthetic trans fluid

[genphreak]

Such as synthetic replacements for Dexron II & III?

I know one can change to CHF 11S or whatever. What is the difference- these power steering systems appear to have the same steering box, lines and reservoirs. Perhaps the pumps are different?

How does putting Dexron in a system designed for CHF/Pentosin affect it? I have synthetic Dexron right here... will it blow seals (how could it if its synthetic- surely its very similar to CHF11S)?

[shogun]

I would not do it!!!!

Pentosin CHF 7.1 is due to the additive employed not miscible with modern high performance hydraulic fluids like Pentosin CHF 11S !! If fluid change has to happen please refer to previously used original fluid, otherwise damages may occur.
http://www.pentosin.de/shop_produkt.php?c=&pid=668&vid=

[Itsnotme1988]

Isn't Pentosin only for cars with SLS/LAD? The other pumps call for ATF IIRC.

[Morgenster]

I would not do it!!!!

Pentosin CHF 7.1 is due to the additive employed not miscible with modern high performance hydraulic fluids like Pentosin CHF 11S !! If fluid change has to happen please refer to previously used original fluid, otherwise damages may occur.
http://www.pentosin.de/shop_produkt.php?c=&pid=668&vid=

I'm still on the fence about this. My mechanic says ATF is no problem for that system and I've been running it for years without issue. What exactly happens when you mix ATF and pentosin 7.1?

[Dave M]

I'm still on the fence about this. My mechanic says ATF is no problem for that system and I've been running it for years without issue. What exactly happens when you mix ATF and pentosin 7.1?

This is good to know and I've often wondered why I spent so much $$ on this dificult to source stuff. Hopefully we gat some sort of consensus.

[Morgenster]

This is good to know and I've often wondered why I spent so much $$ on this dificult to source stuff. Hopefully we gat some sort of consensus.

Well, I'm still on the fence. You never know my power steering could be **** up real fast, but then it'd still be a good question to ask: was it because of the fluid?
ATF is definitely easier to find and every store I go to and ask them to lookup what's supposed to go in there they tell me ATF also.

[shogun]

The question has already been discussed since years on E32 boards. And the decision is:
never replace Pentosin with ATF! Period.

People had damages and people tried to bleed the whole system after the mechnaic or previous onwer put in ATF where Pentosin should be put in.
Leaks occured, small channels blocked then in the system because of abrasive parts and so on.

Just try it, if you want to make your own experience and pay $ for your own experience.
It can be fine for some time/years, but then....
Ask E32 owners which had this problem.

[ryan roopnarine]

i'm pretty sure that bill r, either 3 or 4 years ago, posted an advisory about replacing the atf in non-lad equipped cars with chf 7.1 if the owner was having poor steering performance in really cold climates. i'm pretty sure that this was a bmw document. the document, of course, said that the system must be thoroughlly flushed of the old stuff, though. my car has a cap that says "chf 7.1" but has had atf in it since i bought it. i don't think i've ever seen an e34 with a chf 7.1 cap that actually had chf in it.

[shogun]

Why do you want to risk so many $ in damages. Pentosin you can also buy from VW, MB, maybe cheaper, or you go to RR or Bentley and get your bottle served there on a silver plate
http://www.bimmerboard.com/forums/posts/275263/


Some people from the German 7-Forum and also now from the E34 Forum in German had contacted Pentosin. One got the reply by email, the other one talked with a head of a labority there.

To make it short:

1. Where Pentosin CHF 7.1 is mentioned on the sticker of the reservoir, only refil CHF 7.1.

2. A mixing with other hydraulic oils could cause that addititives could separat as a flocculent , which then could block valves etc. The instruction not to mix is mentioned on the cans of the Pentosin 7.1
That is apparently also mentioned in a special internal BMW info for the workshops.

3. CHF 7.1 contains special lubricants/additives, which are required by the older systems on E32 and E34
CHF 11S does not contain these additives in the required volume, it therefore cannot be used as alternative or replacement for 7.1 in case of tpping up and/or replacments of Pentosin 7.1.

4 CHF 7.1 is green; CHF 11 is also green,but the colour is slightly lighter green.

Here a copy of the email received in Germany from Pentosin:

Guten Tag Herr xxxxxxx,

vielen Dank für Ihre Anfrage, beide von Ihnen genannten Hydrauliköle CHF 7.1 und CHF 11 S dürfen nicht vermischt werden, da es zu Unverträglichkeiten von Einsatzkomponenten bei Vermischungen kommen kann, was wiederum im schlimmsten Fall zu Ausfall des Hydrauliksystems führen kann.
Dies gilt für Nachfüllungen, wie für Neufüllungen.

Wir hoffen Ihnen hiermit weitergeholfen zu haben und verbleiben

Mit freundlichen Grüßen
Deutsche Pentosin-Werke GmbH.

[shogun]

And here an old design from IceTea from Netherlands on Readfly how he tried to find out the best way to get all the wrong stuff out his car
http://img337.imageshack.us/img337/7...aulicsyki4.jpg