If the answer is yes, how often should it be done?

Can you just look at the fluid and tell by its color whether it should be replaced?

Does power steering fluid, like brake fluid, absorb water over time? If it does not, and it also isn't constantly exposed to heat and combustion products (like crankcase oil is), why should it ever be changed? Does its viscocity or ability to lubricate naturally change over time?

 

Don't take my word as gospel, but I really don't think that it is necessary to refill it. I'm basing this on the fact that nobody I know even thinks about stuff like that. If you think something is wrong with your steering- check it right away. I had an '87 Buick that made a horrible sound whenever I turned the wheel and that was an obvious red flag, but otherwise, I'm not really thinking it's something that you need to check. I know I don't check mine.

As for the chemistry of the fluid itself and how it works and absorbs--- don't know

 

I like to change mine at a really long interval. Like 80k miles or something like that. But I've NEVER seen an interval for scheduled replacement of PS fluid in any car I've ever owned. It seems to get black before too long, but that doesn't automatically mean it's bad. Still, I've got a thing about fluids can't possibly last forever.

 

JIm you are correct ,Honda does not say or it has ever said about replacing p/s fluid on any interval at all.

 

Well Honda doesn't have a change recommendation; I agree,.... but on the other hand, take a sniff of the P/S fluid at around 90k miles and then sniff some new from a fresh bottle. The old stuff smells pretty acidic to me. The fluid does go thru hot and cold cycles so it is possible for the fluid to lose stability.

 

I think the fluid gets black from the iron oxide that gets in the fluid from the wear of the pump vanes and from the wear of the seals in the steering actuating piston. I have never replaced fluid in any of our vehicles unless the pump fails due to the shaft seal leaking. I have never flushed any system on any vehicle, but maybe I should since the worn particles would get flushed out. All wear paricles are abrasive just as soot is in dirty engine oil.

I do have a WIX filter on the return line for the power steering on our Chev 1 ton. The power brakes also use the power steering pump pressure.