I posted this in a KIA Forum but wanted to share here in the hope to help you make an informed decision.
Hi, I am just reporting here my experience with my '06 Kia Spectra SX. I've finally hit the 40K mark and about time to do an engine coolant change I decided to inspect the quality and color of the power steering fluid. The fluid had some contamination and it was browning already, but I kind of expected that because I'm a bit of an aggressive driver
So like all of you I check on my manual and online and I see this PSF-3 fluid that no one (neither my KIA dealership parts department) sell. The only reference online I found for a suitable replacement fluid that explicitly say is approved for PSF 3 application is the
Motul Multi ATF. However these lubricants are not sold anywhere near where I live and to get it online is about $11 + about $6-8 for shipping. So I started looking for similar Multi ATF's and found Mobil 1 Fully Synthetic Multi-ATF at my local AutoZone for 7.99 a quart. This fluid is specified for SPIII application just as the Motul fluid does, so I assume this is just a KIA/Hyundai approval thing only. I looked online and compared the properties of these fluids and found that they are very similar and if anything Mobil is a bit more viscous (in my mind I like that, more protection I guess lol) Here are the data comparisons:
Motul Multi-ATF
Density at 20 degrees C 0.846
Viscosity at 100 degrees C (212 degrees F)8.5 mm 2/s
Viscosity at 40 degrees C (104 degrees F) 37.5 mm 2/S
Viscosity Index ASTM D2270 214
Flash Point ASTM D92 208degrees C/406 degrees F
Mobil Multi-Vehicle ATF
Viscosity
cSt @ 40ºC 34.1
cSt @ 100ºC 7.42
Viscosity Index 193
Flash Point, ºC (ºF) 180 (356)
Gravity, API 34.7
Color Red
I did purchase the Mobil 1 Multi-ATF Fluid and did a partial flush. I siphoned the old fluid from the reservoir with a clear tube and made sure to try to get as much contaminant trapped by the filter. I then refilled with fresh fluid and since I had my car up in jackstands for a coolant change I turned the steering wheel a bunch of times
Lastly I redid the whole procedure and this time the fluid came out clear red and free of contaminants (yay!) I used about half quart and I can definitely feel a smoother, quieter steering. I swear is not placebo effect
. My KIA dealer parts guy told me to use regular power steering fluid, but I was reluctant to bring home a 3 dollar Prestone PSF from walmart because I just like to put full synthetic stuff in my car. I will for sure repost something as I drive more miles if i find improvement or not (hopefully not).