2003 330i 68,000 miles
So my car (2003 330i) has been making a whirring/ whining noise that I can hear at idle and low rpm.the noise changes in pitch relative to rpm.it sounds exactly like this for reference. The car groans when accelerating out of slow turns and growls/groans when turning wheel in park. Additionally, the power steering fluid that was in it(CHF11) smelt extremely burnt and nasty. Im quite certain that e46s use ATF not CHF but see so much ambiguity on this question so im not positive. I believe my resovoir has been replaced too making it more unclear, because it says neither “ATF only” or “CHF11 only”. Tonight I flushed the fluid 3 times and filled with Dex/Merc ATF. Will this fix it or is this just a cut and dry power steering pump failure ? Also for helpful background info, the car only has 63,000 miles, PO did all belts and pullies 2 years ago, steering rack too, which obviously rules quite a few things out. Also the power steering system has absolutely no leaks and has never gone low. So if the car is running the wrong fluid it has been for 2 years and probably 12,000 miles. Thank you very much for any insight, obviously want to be sure before replacing a pump as they are damn expensive.