After trying several different PSF and ATF in 2000 MB E430 Power Steering System, I could not stop the whine when engine was hot after driving more than 10 miles. Finally went to Kragen and bought 2 Maxlife PSF bottles, used turkey baster to exchange the fluid. After second fluid exchange the whine reduced 50-60% and reduced 90-95% after 5th fluid exchange. Today I drove the car more than 25 miles and could not hear any whine when the steering was turned more than 15-20 degrees. There is about 5-6 oz remaining from the first bottle for one more exchange, I don't think I need second bottle. I think Valvoline Maxlife PSF is very good and should be used in Power Steering System instead of Dexron III.