Eh all.

My 89 260E makes a weird noise at all times. Its not the bearings as the sound continues even at a stop. Its hard to describe but a constant "wah wah wah" sound like a pump. I did the old turkeybaster method to replace the power steering fluid and it did'nt make a difference. Steering feels fine with no noise lock to lock. The master cylinder has been replaced before I bought the car not long ago. The fuel pump gives a healthy electric buzz sound.

Suggestions as to where to look?

My heater fan, at lowest speed, will make a similar sound you described, especially going around corners.

If your car has climate control, there is a small air pump that sucks air from the overhead map lamp that calculates temps. The pump is located in the side panel, passengers right foot, that also will make similar noise, when bearing get dried out and wear.

Just two things I can think of of the top, but you should be able to determine easily by turning off the CC unit.

Yeah. I never thought of that air pump. Good call. I bought the replacement fuses for the box, so when I have the fuse yanked for the climate control, I'll give a listen. Thanks so much!