Whine after Amsoil PS fluid install.

[Thingfish]

Car is an '04 Subaru STi that uses DEXIII as PS fluid. Last time I changed the fluid in the car for the owner, I used Amsoil Uni. ATF.
Car is currently back for it's 60K maintenance, and a PS flush is on the list. This time I had Amsoils PS fluid so I used that as a replacement.
Upon starting the car had a new whine that got worse with any wheel movement. Checking the fluid after shutting the car off showed a lot of foam. To the point of it being an inch above the MAX line on the reservoir. I evacuated the fluid twice with a 30 sec run in between with Uni. ATF and the whine and foam is gone.


WTH!?!?!

 

[Boomer]

Well, if it called for ATF, why did you add a different fluid?

 

[Thingfish]

Like I said, I had it. And Subaru is on the list of car makers the fluid is made for.


So just FYI, the Impreza does NOT like Amsoils' PS fluid.

lol....

 

[Pablo]

I have reported your findings to Amsoil and asked some questions. This is the first I heard of such a thing. Did you go lock to lock? The foam (and noise) point to something like a pump cavitating, or pumping dry or some chemical interaction perhaps.

 

[ZZman]

Make sure you crank the steering wheel back and forth many times with the cap off to get the air bubbles out.

 

[PT1]

Many toyotas are also speced with DexIII and don't like anything else. So why fight it?

 

[Pablo]

So I got a reply from HQ:

Quote:
Our power steering fluid is not recommended for power steering units that are calling for ATF. That Subaru is calling for a Dexron III type fluid so changing the fluid to ATF should eliminate the noise coming from it.


So I look your car up:

Quote:
Fluids
Power Steering Fluid.....AF3
Synthetic Automatic Transmission Fluid
Torque-Drive™ Synthetic Automatic Transmission Fluid (ATD)

 

[mechtech2]

It may have been OK when properly purged of air.
Time is not on your side with a customer waiting, but I can't condemn the fluid yet.

 

[unDummy]

Flush it with ATF or ATD.

If the PS calls for ATF, use ATF. If it calls for PSF, use PSF.

A switch to the required ATF is required now. But, I believe that your PS probably took in some air. Once its purged, the noise should go away.

 

[Thingfish]

Lock to lock, back and forth repeatedly for several minutes was the first thing I tried. The foaming/noise never improved. It has been flushed multiple times with fresh ATF and all symptoms are gone, instantly.

That is what I get for not checking the Amsoil site.... Because saying it's for Subarus, on the bottle, doesn't mean, it's for Subarus..