Dexron VI in a power steering system

[Vaca]

My Lexus is speced for Dexron III for the power steering system. I've changed it several times using the turkey baster method. I'm considering changing it over to Dexron VI instead of the speced D-III.

Any thoughts?

My thoughts are that the D-VI starts (and maintains its lower viscosity) a bit thinner, which I'd think would be good for the cold winter months. I'd also imagine the seal compatibilty would be very close between the D-III and D-VI.

Thanks in advance for any input.

 

[JohnBrowning]

You are always ok upgradeing to the newer spec. of a given product. So you can use Dex III in something that says use Dex II. You can not though go the other way unless it is an emergency. So you will be fine with DexIV.

 

[unDummy]

Shouldn't be a problem. But, there are plenty of synthetic ATFs that will perform just as well(or even better).

 

[Vaca]

I'm considering the D-VI since its viscosity is a little bit lower than D-III (mineral and synthetic?) and the steering is a little sluggish first thing after a cold start during the colder winter months. I think the D-VI would be better than a syn D-III in this regard....but I may be wrong...

 

[Mokanic]

As a Toyota tech. I would highly suggest using a synthetic fluid in your Lexus. Most people don't realize how hot and how much Toyota's pumps shear oil. I can say that at least 80% of Toyota's steering failures are lubricant failure related.
Dexron will work but I would spend the extra for a full syn. if thats what you want to use.
Royal Purple makes an excellent p.s. fluid.
Lubeguard makes an excellent p.s. fluid
Lubeguard also makes a p.s. additive that will bring a mineral fluid up to syn. specs.
Stay away from over-the-counter seal-swelling snake oils. If your system is not leaking you don't want that stuff in your p.s. system. They all are very acidic and will do more harm than good in the long run.

 

[Vaca]

Thanks Mokanic.

Both my Lexus and my Toyota are speced for Dexron III. Do you suggest I use a synthetic D-III, or use a good quality synthetic PS fluid like you mentioned in your above post?

 

[RogerKlugerAus05]

I have 2 Toyotas, a 2005 Kluger/Highlander awd and a 2006 Corolla. I intend to replace the p/s fluid on both with Redline fully synthetic fluid by emptying the resevoir and filling with Redline several times. Just peace of mind as I have Redline in tfr box and diff on Kluger and gearbox (manual) on the Corolla and when they are out of warranty intend to use Redline engine oil on annual oci.
Roger

 

[unDummy]

Simply compare specs with your weather:

brand: -40*c brookfield, 40*c visc, 100*c visc, VI, PP*c

~DexronVI: 12000, 30, 6, 150, -51
Pentosin 11s: 1100, 19, 6.0, 320, -55
Mobil1 ATF: 5190, 34, 7.6, 199, -54
Redline D4: 5200, 34, 7.5, 198, -60
Redline PSF:18000, 34.7, 6.5, 143, -50

I'd still stick with M1 or D4. I prefer a little thicker oil for 'film thickness protection'. And, they'll probably shear a little into the ~6.5 range soon enough.
For ultimate performance, the 7 and 11s Pentosin fluids can't be beat. They're are as thin as DexronVI. And, the ultra high VI index allow the Pentosin fluids some incredibly cold flow performance.

On a budget any MerconV, multivehicle ATF, and ATF+4 are upgrades to standard DexronIII/Mercon fluids.

Another plus of some DexronIII/Mercon is that they are recommended for pump and industrial applications like Sundstrand, Eaton, Vickers, Caterpillar, Allison, Denison,....

Does GM or any DexronVI supplier recommend it for anything besides GM transmissions??????

 

[Mokanic]

I have been with Toyota a long time and from what I have seen, mineral based Dexron would be my last choice. If Dexron was going to be used I would choose a full syn. like M1.
By far my first choice would be a full syn. power steering fluid.
In my Toyotas I have run Royal Purple. Any repairs that I do on my customers TOYOTA or Lexus steering systems get this fluid. It is a super fluid and isn't priced as high as you might think.(retails about 7$ aqt. for PAO base.)

In my customers Hondas I use Lubeguard's Honda fluid. The reason I use the Lubeguard in Hondas is becouse it is approved for use in Hondas. Keeps my but out of a sling. The Royal Purple would work just as well and I run it in my daughter's Civic.

If Redline makes a fluid you can bet it is also good. Everything they make is.

I have seen alot of steering related problems that would not have happened if a fluid like Royal P. Lubeguard,or Redline had been used. Dexron is simply a compromise fluid that can be used in more than one application on a car which makes it easier on the manufacterer. If you choose to use it just change it every 30K and it will do.

However,it is foolish to say it will handle high heat and shear like a PAO or ester based fluid can. It's like comparing regular dino motor oil to a polyol-ester oil in blistering high heat. Both will work but one is going to deal with the heat much longer and protect better in the long run.

 

[Vaca]

Thanks for all the thoughtful replies.

I'm sold on the need for synthetic in a Toyota/Lexus PS system. I'm in between two choices now, either Mobil 1 synthetic ATF or a synthetic power steering fluid such as RP that Mokanic mentioned.

I'd really like to use a dedicated PS fluid, but my only hesitancy is that I've never seen it in writing where you can use PS fluid in a Toyota or Lexus. The only spec I've ever seen is for Dexron III. The only potential problem using PS instead of D-III might be the seal swell properties. I'm not an expert at this by any means, but it's hard for me to imagine that there's much of a difference in seal swell properties (or others for that matter) between the two types of fluid. But, again, I've always seen just D-III speced.

Right now, I'm leaning toward just simple Mobil 1 synthetic ATF since is so easily availible locally. Cost is not much of a factor, especially since I'll only need one or two quarts.

 

[Auto-Union]

Guys, don't use the turkey method. Simply disconnect the Resevior OUT / Pump IN hose at the Res, cap the hole in Res with tin foil, Insert a small funnel into the hose and pour in new fluid, cranking with the ignition disconnected. Drain the Res and do it like 3X....you will see new fluid fill the Res. If doing an old system, do it with plain fluid first, drive a few days and do it again with premium fluid.

 

[Vaca]

AU, I agree the full drain through the hoses certainly effects a more complete fluid change. This works well on cars that have decent access to those lines. There are some cars where getting to the hose is more difficult than it's worth, so the turkey baster works well in those instances IMHO.

 

[todds21]

I did this on my wife's ES330 this weekend. I did the turkey baster method and am refilling with Amsoil ATF. I used the Amsoil in my old Tacoma's power steering system and liked it. Still need a couple more drain and fills till I will be satisfied that I got all the old ps fluid out. I bought a suction gun from the auto parts store that worked better for me than the turkey baster i tried.