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Power steering fluid options - DEXRON VI?

Buick Ownership
1999 Buick Park Avenue Ultra (Supercharged)
Hi, I am going to be doing a fluid and filter on my transmission soon (rebuilt, has 20k miles and a few years on it. Wanna stay up and keeping it running strong.) And I will be buying a lot of DEXRON VI since I have a lot of GM vehicles. Could I use it as power steering fluid? I know some cars, notably a lot of fords, call for Mercon as their PS fluid. In this case, Its a nice high quality synthetic and I want a nice high quality synthetic in my ps system. It needs a flush and it has contaminents causing the Power steering to work pretty poorly, so I want to flush it out and then refill. Can I use dexron 6?


Full Member
Buick Ownership
2007 Lucerne CXL. and 1995 Lesabre currently, past 1973 Riviera, 1968 Riviera
While DEXRON VI has / is being used on power steering system in newer vehicles and it "may" work on older models it's more if the seals and the rest of the system would be able to operate properly and if the entire PS system could be completely drained. It's a 50/50 conclusion on this, so considering it's a one time flush, the minimal amount of fluid that's needed stick with PS fluid and know it will work.


Full Member
Southern Utah
Buick Ownership
2003 Park Avenue Ultra
Personally, I run Royal purple power steering fluid in everything I own that requires PS fluid. As the systems get older they get noisy due to increased wear and tolerances opening up. It has removed the noise on every pump I have ever used it in. Full synthetic, fairly priced, seal conditioners, detergents, etc. It's only a 5 year fluid, but it works very very well.

Considering a lot of power steering systems can see 1500, 2000, even 4500+PSI(especially 90's Dodges!) is why I stick with the PS fluid. It is designed to handle crazy PSI. My Mopar road race car saw 5500PSI spikes near full lock steering at 9200rpm and idled at 2000PSI. Granted that had an aftermarket cooler and -6AN reinforced 10K PSI lines, but the pump was stock and it was underdriven by 15%.

The newer systems are using a lower pressure, compared to the older systems, as well as power steering coolers standard, so Dexron and Mercron work for them now. We can thank Honda for pioneering the 750PSI system in the early 90's and getting it down to 500PSI now. I stick with power steering fluid if it doesn't specifically ask for a thinner fluid such as DOT4 or an ATF.