Today when I got into my car, it started making a rather loud humming noise that wouldn't go away even after wating a few minutes. The noise seemed to be coming from the front of the car, somewhere close to me. I'm not sure if this is at all related to the fact that the temperature dropped dramatically in last couple of days (and I doubt it's related to my rear brake pads that need to be replaced), the car makes noise even when standing still. I noticed that the noise seems to get slightly louder as I turn my steering wheel left. I also noticed that the noise went away after I got on the freeway, but came back after I got on a normal road with slower driving speed (I could have just stopped noticing it due to highway driving being louder). I did a quick search, and found that humming could be indicative of fuel pump problems, clutch bearing or exhaust (probably not the last one, since the noise is coming from the front of the car).

 

Your power steering fluid is low. Audi's power steering fluid is notorious for compressing so much when it gets cold that the pump cavitates air, creating the hum and some steering feedback.

 

Should I just refill it or completely change it? The way I understand from doing some research on the forums is to refill it I just pour more into the tank with green cap, to change it I'd have to partially take front-light assembly off which looks like a PITA (I still have bad memories of changing out the wiper transmission)? If I have to change it, should I take it to the dealership (or would it be too expensive)?

 

I'm in the same boat. dropped to 24 in CT. Hoping that adding fluid will do the job. Weekend warrior part 1! Good luck

 

Well, it got down to 1F here in MN and I haven't noticed this issue yet with my car, but I wonder what happens when the fluid warms back up. When the temp comes back up, since there's nowhere for the volume to expand (assuming you filled it up when it's cold), the pressure in the power steering system will have to rise. Could it rise to unsafe levels, or does the factory just "underfill" it in the first place?

Secondarily, could we just drain the system completely and refill with a fluid which has a smaller coefficient of thermal expansion in order to completely avoid this issue in the future? Is there something special about the fluid the factory uses that makes it necessary to continue using the same stuff?

 

Guys, I need more advice. I checked the steering fluid today, it was indeed low, the dipstick stayed completely dry (I did see the fluid in the tank though). I called the dealer, the g