Replacing ATF in power steering with Pentosin CHF 11S?

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I'm looking into replacing the power steering fluid in my 1998 Volvo 945 Turbo with Pentosin CHF 11S. Mainly because of the improved cold flow characteristics since I live above the arctic circle and temps regularly drop below -30C (-22F) during wintertime. I'm currently running Mobil 1 Synthetic ATF and it did improve the steering assist on really cold mornings compared to the dino ATF that I put in it before, but I think CHF could potentially improve it further.

What I'm wondering is if there is any reason as to why I should avoid doing this? Its the original steering rack and pump at 350k km (220k miles) and everything is nice and dry (as in no leaks) and works fine beyond the reduced power assist on arctic mornings, so if there is any risk of causing problems I'll probably just be happy with the Mobil 1 ATF as it is.

Owners manual just states "ATF" for the power steering and doesnt call for any particular specification beyond that. I'm mainly worried about seal compatibility and I find conflicting information on the internet if it is a good idea to make the swap from ATF to CHF so I turn now to you guys!

Thanks. Happy to have joined this forum today, seems like a nice community.
 
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Not sure if CHF 11s is correct for your vintage of Volvo or not. On my wife’s S60, the manual says the same as yours, but CHF 11S is the correct fluid. Hopefully someone else will chime in, but I can’t see there being any issues either. It’s a superior fluid.

I switched her car over 7 years ago. Has about 220k miles on it now. No leaks. No idea what was in it before.

I let it get away from me and the fluid turned dark brown. Bought a 4 liter jug from FCP Euro and did several drain and fills with a turkey blaster until I was removing fluid as green as the new stuff. Going to start doing a drain and fill at every oil change from now on.

*To add to the above comment on compatibility, I would do several drain and fills when switching over. The first 2 or 3, just run the engine and cycle the steering lock to lock 20 times or so. Do drain and fills after your daily commute until green.
 
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The fluids are not compatible but the ATF can be flushed to use CHF11s, it will take quite a bit of fluid to do this or you could try a return line off exchange and filling with a lower viscosity ATF like DEXRON VI/MERCON LV that is compatible.
 
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I'm looking into replacing the power steering fluid in my 1998 Volvo 945 Turbo with Pentosin CHF 11S. Mainly because of the improved cold flow characteristics since I live above the arctic circle and temps regularly drop below -30C (-22F) during wintertime. I'm currently running Mobil 1 Synthetic ATF and it did improve the steering assist on really cold mornings compared to the dino ATF that I put in it before, but I think CHF could potentially improve it further.

What I'm wondering is if there is any reason as to why I should avoid doing this? Its the original steering rack and pump at 350k km (220k miles) and everything is nice and dry (as in no leaks) and works fine beyond the reduced power assist on arctic mornings, so if there is any risk of causing problems I'll probably just be happy with the Mobil 1 ATF as it is.

Owners manual just states "ATF" for the power steering and doesnt call for any particular specification beyond that. I'm mainly worried about seal compatibility and I find conflicting information on the internet if it is a good idea to make the swap from ATF to CHF so I turn now to you guys!

Thanks. Happy to have joined this forum today, seems like a nice community.
I think that it has to do with viscosity and flow only, so it doesn't really need all of the ATF properties. I think you'd be OK and improve the steering.
 
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I've heard you have transmission heaters there as well as engine heaters. How 'bout an electric blanket for the PS reservoir?

To dlundblad: I'm on my 3rd V70. I used copper wire to hang a doughnut shaped magnet (real strong) in the reservoirs.

As a child, I feared flat tires on my bicycle...always a time wasting PIA. As an adult a leaking PS rack is my new constant fear; ergo the magnet.

I use CHF-11S in everything except Hondas. I never want a, "What did you use?" conversation with a Honda owner.
 
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The fluids are not compatible ...

Beyond that and the difficulty flushing it fully, I very seriously doubt the Pentosin is going to get you much better performance than the M1 synthetic.

The Pentosin was popular in extreme cold conditions when full synthetic ATF hydraulic fluids were not around. Today, the marketplace is very different. I would keep using the M1 and feel very confident, as well as avoid the hassle and expense.


Actually, pulling up the specs, a quick guess based on pp, etc. is that the Pentosin would perform WORSE than the Mobil 1 ATF.


 
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To dlundblad: I'm on my 3rd V70. I used copper wire to hang a doughnut shaped magnet (real strong) in the reservoirs.

I put these in; some proper filtration and a BIG magnet. The hose routing on these cars makes installing them quite easy.


IMG-3693.jpg
 

Redblocker

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I lean towards just staying with the M1 for now as I had another look at the spec sheets for the fluids. CHF 11S has a pour point of -57C and M1 ATF is at -51C. I remembered M1 having a specified pour point of -40 something but I must have mixed it up with some other fluid I looked at during my research. The performance probably wont improve all that much as Oro stated. Regardless I'm thankful for all the info, I may put Pentosin in it when it comes time for a fluid change.

As for those PS filters I installed one of those on the return line at the PS reservoir and had it there for about 15-20k km until I removed it since I thought I heard my PS pump squeal a little, in hindsight I'm pretty sure it was the water pump as I knew it was going bad anyway but I wanted to eliminate the filter as the reason for the squealing (increased line resistance and/or air pocket etc). I cut it up after removal and the magnet had trapped a gooey surface of metal particulate, I dont think any of the three previous owners ever changed the PS fluid.

For those of you using those PS filters how often do you change them?
 
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Those power steering filters might make the steering even more stiff in the cold. Atleast it did for me using ATF.
 
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If you want something thinner that should have compatibility with ATF you could try redline ATF it's got about the lowest rated pour point and brookfield at -40 of any ATF I've seen whether it be d4(dex/merc equivalent) or d6 (dex6/merc lv equivalent).
 
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I use that CHF11S in my '06 SAAB 9-3 and it works fine. It's what the owner's manual calls for. Your Volvo probably does too. Welcome to the forum. Lot's of SAAB and Volvo enthusiasts here.

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JHZR2

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I’d find the lowest viscosity atf that I could. Some of those pentosin hydraulic fluids aren’t compatible with others (though I thought it was more related to the 20s fluid), and I wouldn’t want my high mileage AT system to be the Guinea pig.
 
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I have no meaning about what o-ring material and what your Volvo is speced for in the first place. But I have a personal experience with CHF11S that is worth to note. I once spilled some CHF11S on to a regular o-ring (black one). Over night it swelled up to 10x the size and had a completely jell-o (gel) consistency. So if the PS system doesn't have the right (green I suppose) o-rings, problems can be massive.
 
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