Steering pump noise

[Breeze1]

Hello everyone,

So here is the deal: when I recently swapped my engine (M52TUB25 > M52TUB28), the steering pump was swapped over from the old engine to the new one (the Castrol oil as well, since it had been replaced only recently). And it seems that it didn't appreciate that, since it started making that whining sound, intermittently (it seems to be more present when the engine is either cold or really warm, after driving in traffic jams for a while).

I thought about changing the oil once again, from Castrol to Febi, to see if it makes a difference, but I'm not sure that would be a good thing to do since the last time a steering pump failed on me, my attempt to improve things by changing the oil only made them worse and I went from a relatively annoying noise to an unbearable one and a stiff wheel, which forced me to change the pump.

I regularly bleed it from air and there is no air in the system (no foam or anything when opening the tank).

So basically I'm open to any suggestion you might have to get the noise level down (additive? specific oil brand/grade? Some procedure I'm not aware about?).

Thanks.

[MarcoZandrini]

The proper power steering fluid is Dexron3. All E46s use this power steering fluid.

[Breeze1]

I'll have to double-check in the trunk of the car, see what I have, but I think that's the one I have used (Castrol/Dex III, green packaging). It seems to be behaving well under ideal temp conditions, but having a hard time to handle high temps...

[bmwdirtracer]

Dex 3 is Dex 3, no matter whether it's made by Castrol, Febi, or Autozone. It's generic - the difference is only in the price.

Now, a noisy pump is caused by one of a few different issues:
1) Clogged filter screen in the reservoir. (The reservoir is like twenty bucks, and has a filter. You should change the reservoir, with the fluid, every ~80 to 100k miles.
2) Clogged restrictor hose. One hose in the system has an inexplicable splice. That's the restrictor.
http://www.realoem.com/bmw/enUS/show...diagId=32_0958 see part 3
3) dying pump

....of course, I'm assuming the fluid is to the full level of the dipstick.

[Breeze1]

Thanks bmwdirtracer, I'll look into it. If I understand well, the one with the inexplicable slice is n°3 right?
N°1 and 11 have been replaced recently, as well as the pump. The reservoir was not swapped over from the old engine, since it seemed to be in fair shape, judging by the engine itself, which seems to have a low mileage (japanese market, no leaks, etc.).

[bmwdirtracer]

You can call me Chris.....yes, part #3. If you happen to have a spare reservoir, might as well swap it. You might even want to try removing part 3, and blowing backwards through it, with compressed air, just in case there's a blockage at the restrictor which you might clear, for free. That's actually worked for me at least twice, in many years....it's worth a try.

[Breeze1]

Alright Chris, I will try that (reservoir swap+part 3 cleaning+ oil change), thanks!
Nayl.