ATF -vs- PS Fluid..
12-26-2018, 03:29 PM
#3
From Google, FWIW:
https://www.quora.com/Can-you-use-tr...-steering-pump
https://itstillruns.com/substitutes-...d-6762594.html
https://carfromjapan.com/article/car...steering-pump/
https://www.quora.com/Whats-the-diff...smission-fluid
https://www.quora.com/Can-you-use-AT...power-steering
https://www.quora.com/How-does-power...r-from-ATF-oil
https://www.bobistheoilguy.com/forum...&Number=497271
https://www.quora.com/Can-you-use-tr...-steering-pump
https://itstillruns.com/substitutes-...d-6762594.html
https://carfromjapan.com/article/car...steering-pump/
https://www.quora.com/Whats-the-diff...smission-fluid
https://www.quora.com/Can-you-use-AT...power-steering
https://www.quora.com/How-does-power...r-from-ATF-oil
https://www.bobistheoilguy.com/forum...&Number=497271
12-26-2018, 04:37 PM
#4
Rennlist Member
What I do know is back in the day a helpful oil changing attendant put the wrong ps fluid in my Honda Prelude that used power steering fluid and it trashed all the seals in short order.
12-26-2018, 10:08 PM
#5
Rennlist Member
These days I have seen German built cars (GM-Opel eg) running real hydraulic fluid in their PS systems. Not sure about VW, Audi etc. Most others use ATF in my experience - Japanese for sure.
jp 83 Euro S AT 57k
jp 83 Euro S AT 57k
12-26-2018, 11:36 PM
#6
Former Vendor
I only use ATF in 928 power steering systems.
My simple brain tells me this: It's so easy to use what the manufacturer says to use...why fight it?
12-26-2018, 11:38 PM
#7
Rennlist Member
Thread Starter
You ask 20 people this question and you will get 22 different answers. It takes way too many brain cells to try and figure this out...and if you choose wrong, the results are costly. Just use what the manufacturer suggests you use. My hydraulic lifts say that either ATF or hydraulic fluid can be used. I use hydraulic fluid...and would not consider mixing ATF with it, for some reason I'm not sure of. My log splitter came with no instructions on what fluid to run. It had hydraulic fluid in it, when delivered, so I use that (and it "seeps" from virtually every seal and blows hoses on a regular basis. My Kubota tractor was pretty expensive and the replacement parts make Porsche parts look like Porsche is giving them away...so I use genuine Kubota fluids and filters. Cheap insurance, as far as I'm concerned, plus it doesn't leak, so only the hydraulic fluid changes are expensive. My Toyota fork lift doesn't leak, so I haven't had to figure out what to use in it, yet...
I only use ATF in 928 power steering systems.
My simple brain tells me this: It's so easy to use what the manufacturer says to use...why fight it?
I only use ATF in 928 power steering systems.
My simple brain tells me this: It's so easy to use what the manufacturer says to use...why fight it?
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12-27-2018, 12:28 AM
#8
Former Vendor
12-27-2018, 02:14 AM
#9
Rennlist Member
Jeff,
As I am aware the principal difference between ATF and pukka "power steering fluid" is that traditional ATF is mineral oil based whereas out and out power steering fluids are silicon based. The mineral oil tends to be harsher on seal materials than silicon based hydraulic fluids that some systems are specified to use. Thus stick ATF in non such specified systems and the seals will likely fail in no time when exposed to a mineral oil based ATF.
Some manufacturers specified their power steering systems to be compatible with ATF as Porsche did for the 928. What they specify for use in current models I have no idea but it seems that in the timeframe our 928's were being made it was common for some manufacturers to specify use of ATF in their power steering systems. What percentage of vehicles had such spec and why they did this remains to be seen.
As I am aware the principal difference between ATF and pukka "power steering fluid" is that traditional ATF is mineral oil based whereas out and out power steering fluids are silicon based. The mineral oil tends to be harsher on seal materials than silicon based hydraulic fluids that some systems are specified to use. Thus stick ATF in non such specified systems and the seals will likely fail in no time when exposed to a mineral oil based ATF.
Some manufacturers specified their power steering systems to be compatible with ATF as Porsche did for the 928. What they specify for use in current models I have no idea but it seems that in the timeframe our 928's were being made it was common for some manufacturers to specify use of ATF in their power steering systems. What percentage of vehicles had such spec and why they did this remains to be seen.
12-27-2018, 02:14 AM
#10
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
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I was really bored one winter day years ago. Long story short to my conclusions which are probably wrong. If you lined up every possible power steering fluid on one side of the room, and every known possible ATF on the other side of the room. Two bottles from each side of the room might have the exact same ingredients.
So you either pick the ATF bottle that matches the manual or take a random guess which PS bottle is the correct one.
If you want to have some fun, get dirty with vintage Audi's, I had three of those cars. If you even talked about running anything but Pentosin Mineral Oil Power Steering Fluid in these cars, the pump explodes.
"You ask 20 people this question and you will get 22 different answers"
That's not funny. I asked this question at the GM dealer for my 2003 Denali, talked to 3 different people and I honestly received 4 different answers.
So you either pick the ATF bottle that matches the manual or take a random guess which PS bottle is the correct one.
If you want to have some fun, get dirty with vintage Audi's, I had three of those cars. If you even talked about running anything but Pentosin Mineral Oil Power Steering Fluid in these cars, the pump explodes.
"You ask 20 people this question and you will get 22 different answers"
That's not funny. I asked this question at the GM dealer for my 2003 Denali, talked to 3 different people and I honestly received 4 different answers.
12-27-2018, 08:54 PM
#11
Rennlist Member
I have a 928S of 1980 and have the old steering pump (non-alu) like all early 928 Porsches.
Porsche recommends ATF Dexron II (mineral oil), but my experience with mineral oils is that they deteriorate rapidly .
Thus, I checked the specs (viscosity, fluid point...) of the early Dexron and checked them with the new Dexron ATF compatible silicon oils.
I found that Champion ATF Dexron III was a match regarding the specs, and it was Silicon based and also red.
So make sure the specs and colour match.
I have been using this oil for almost 10 years now. No issues whatsoever .
Porsche recommends ATF Dexron II (mineral oil), but my experience with mineral oils is that they deteriorate rapidly .
Thus, I checked the specs (viscosity, fluid point...) of the early Dexron and checked them with the new Dexron ATF compatible silicon oils.
I found that Champion ATF Dexron III was a match regarding the specs, and it was Silicon based and also red.
So make sure the specs and colour match.
I have been using this oil for almost 10 years now. No issues whatsoever .
12-28-2018, 08:25 AM
#12
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I've never been quite sure what silicone-based things are made of, so I just looked it up. I had presumed silicon was substituted for carbon in otherwise normal hydrocarbons, which is why Star Trek featured silicon-based lifeforms. But no - the polymer backbone is [-Si-O-Si-] with hydrocarbon groups attached to the silicon atoms. Impress your friends by learning the more accurate term - polydimethylsiloxane, or PDMS. At the very least, don't neglect the "e". ZZZZZZZZZ.
Interesting from a 928 perspective: silicone oils are considered non-flammable. Good for flatulence, too.
Interesting from a 928 perspective: silicone oils are considered non-flammable. Good for flatulence, too.
