Audi A6 Power Steering Groan

Help me help my neighbor - he's got a C5 generation A6 that just came back from the shop after a timing belt and water pump replacement job. It has a new problem it didn't have before it went in, that being a groan from the power steering, most pronounced at idle speeds. It drives fine, no hard spots in the steering, no leaks visible, no noise with the wheel centered. The noise isn't really audible outside the car but is obvious in the cabin. The shop that did the work said something about a hose near the pump looks corroded and may be allowing air to leak into the system, and has that hose on order. Sounds like BS to me... Any common reasons for this malady?

Hopefully he checked the fluid level? My TDi groaned a bit until I checked the fluid and found it low. After it was topped up and cycled a few times to get air out, it's been quiet.

Fwiw, I've read in a few places the VAG cars are VERY sensitive to the power steering fluid. VAG fluid only. Unfortunately, the stuff is not cheap.

Thanks. Doubtful he checked the level and it was dark when he showed me the car. I'll try to check the level tomorrow, and if he needs more I'll make sure it gets the right stuff - I'm guessing Pentosin CHF which I have some of but I'll check.

I had a same area A4 that would loose fluid everytime it first got cold every year. Didn't loose fluid any other time, only when it got cold, filled it up at the beginning of the season every year. Never had any other trouble with that system.

pigeon wrote: I'll make sure it gets the right stuff - I'm guessing Pentosin CHF which I have some of but I'll check.

Doesn't sound familiar, but that might be it. I ended up buying a quart at the local dealer since I needed it ASAP. IIRC, it was about $30. Not as bad as MINI transmission fluid, but close.

Gotta use the OEM Pentosin in that system. Make sure it's not low, check the hoses for leaks, may need a new PS pump...

NAPA has the pentosin now, fyi.