Pentosin CHF 7.1 / 11S Help

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MSGGrunt
Posts: 520
Joined: Fri May 15, 2015 4:43 pm
Location: Western, MA USA

Pentosin CHF 7.1 / 11S Help

Post by MSGGrunt »

I know the fluid in my 1987 M6 SLS currently is filled with the 7.1 mineral oil based fluid and according to Pentosin's web site the 11S is only different in that it is a synthetic fluid and according to their web site they state that in the power steering system one fluid should not be mixed with another. Mineral oil mixed with synthetic. With the 7.1 getting hard to find and expensive if I switch to 11S should I drain all of the mineral based 7.1 out of my SLS or can I just top off with 11S? Or does someone know of a source for the older 7.1?


PENTOSIN CHF 7.1 (White container with GREEN cap) - A mineral oil based fluid. Operating temperatures range from -40°F (-40°C) up to +212°F (+100°C).

PENTOSIN CHF 11S (Green container with RED cap) - A synthetic based fluid. The latest development based on CHF 7.1 technology. Operating temperatures range from -40°F (-40°C) up to +266°F (+130°C). This product is especially formulated for the latest technology where fluid characteristics influence safety and performance.


IMPORTANT NOTE: If vehicle specifications state CHF 11.S there is no substitute, however, if vehicle specifications state CHF 7.1, CHF 11.S can be substituted. Further, Pentosin CHF fluids should not be mixed with ATF fluids. Please check the reservoir tank and owner’s manual for indication of what type of fluid was original fill. The hydraulic systems for power steering must be drained as completely as possible when changing from one type of fluid to another.
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Brucey
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Re: Pentosin CHF 7.1 / 11S Help

Post by Brucey »

some info here that might be useful;

https://www.bobistheoilguy.com/forums/u ... er=2440316

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
MSGGrunt
Posts: 520
Joined: Fri May 15, 2015 4:43 pm
Location: Western, MA USA

Re: Pentosin CHF 7.1 / 11S Help

Post by MSGGrunt »

Thanks Brucey. Maybe it is just time to flush the system and change over to the newer synthetic Pentosin 11S.
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dwcains
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Location: Lutz, FL

Re: Pentosin CHF 7.1 / 11S Help

Post by dwcains »

That's what I did with mine. I drove it for a few tanks of gas, and then did it again, just to get all the old stuff out. Haven't had any problems. I've also heard of using the Redline synthetic ATF in the system, but haven't tried that, and the new Pentosin was easy to source.
Dean
Lutz, FL

'85 635 CSi Euro #9402254
'87 Spider Veloce
'92 Spider Veloce
'08 350Z

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Sbeaud
Posts: 279
Joined: Fri Jan 04, 2019 9:38 pm
Location: Okahumpka, Florida USA

Re: Pentosin CHF 7.1 / 11S Help

Post by Sbeaud »

Resurrecting an old thread here with a similar question.

My SLS system fluid is low. I'm assuming since I don't know the fluid in the system, and Pentosin does not recommend mixing fluids, I need to replace the fluid? If so, what's the best way to do that? As lazy as I am I don't want to disassemble the entire system to purge shocks, accumulators, valves and reservoir.

Is Pentosin CHF 11S the accepted alternative?
https://www.fcpeuro.com/products/hydrau ... 1s-1-liter

Thanks

Scott
1988 M6
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Sbeaud
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Joined: Fri Jan 04, 2019 9:38 pm
Location: Okahumpka, Florida USA

Re: Pentosin CHF 7.1 / 11S Help - Leaking SLS

Post by Sbeaud »

After posting I was expecting someone to respond with "If it's low you probably have a leak...". Well I checked today and it looks like the left shock is leaking.
1988 US M6 Left Rear Shock.JPG
1988 US M6 Left Rear Shock.JPG (266.73 KiB) Viewed 2086 times
1988 US M6 Left Rear Shock-2.JPG
1988 US M6 Left Rear Shock-2.JPG (249.75 KiB) Viewed 2086 times
1988 US M6 Left Rear Shock-3.JPG
1988 US M6 Left Rear Shock-3.JPG (97.43 KiB) Viewed 2086 times
I think the only alternative is to replace? Based on the following thread I think a reseal is a no-go.

viewtopic.php?f=17&t=29173&p=210477&hilit=sls#p210477

Make sense?

Also, I ended up buying 2 liters of the Pentosin CHF 11S from FCP Euro.

Thanks

Scott
1988 M6
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