Problem: 03 A4 3 liter power steering begins to moan and whine once warmed up. Mileage 107k. I am third owner. Previous owner had rack replaced under extended warranty at 62k miles due to very noisy operation.

Troubleshooting:
1-Fluid does not look very "green" in PS reservoir.
2-Fluid seems to have lots of bubbles (almost foamy) in reservoir when engine running at idle.
3-Pump located at top front of engine between banks of cylinders has older fluid residue around area of hose from reservoir connection on to pump. Area cleaned and inspected. Appears that there is a poor seal of the clamp on hose at pump inlet.
Observation: Normal fluid level in reservoir is almost level with or slightly lower that pump inlet hose connection.

Decided to replace original crimped metal clamp on hose at pump inlet but did not have on hand. Temporarily installed 2 ea heavy duty zip ties, one each side of original metal band clamp.
Removed belly pan (sorry my nomenclature....) and removed clamp and hose from return line from fluid cooler loop coming back through from in front of radiator. Plugged hose that is return to reservoir. Connected clear plastic drain line to line from cooling loop. End of clear plastic hose placed in clear container to capture old fluid.
Filled reservoir with new proper green mineral PS fluid from Audi Dealer. Started motor and let run about 2 seconds. Shut off motor. Reservoir empty. Refilled reservoir. Repeated 2 second run procedure. Fluid from clear plastic hose NOW green and clean. Again filled reservoir and repeated 2 second run.

Removed plug from return hose to reservoir. Removed clear tubing from reservoir end of cooling loop metal line. Reconnected hose from cooling loop to reservoir return. (Return line is smaller diameter of 2 reservoir hoses.) Filled reservoir to just slightly above normal range and started motor. Within 3-5 minutes no more bubbles were witnessed in reservoir AND there was NO MORE whining or moaning from the power steering system.
Original equipment band clamp has been replaced with standard stainless steel screw type band clamp.

Vehicle has been driven 300 miles in 10-15 degree f temperatures and no noises heard from steering system. Steering feel and smooth operation lock to lock.

Due to the low level of the reservoir I suspect that once the fluid and hose warmed up that air was being sucked past the poor seal at the pump inlet but the fluid did not leak out much since fluid will not gravity feed up hill.

Note: Did find a few golden colored small flakes in drained fluid and do question the parentage of the fluid that was in system prior to flushing.

Gets me to thinking.... If I had dealer look into it would they have changed pump ($400+ new) AND of course properly secured hose at pump inlet... Problem solved either way but glad I was able correct with just a few feet of plastic tubing from Lowes and one liter of VW/Audi mineral PS fluid!!

2old2turbo

 

thanks for this fix
i have a 1997 A6 with 100k and have noticed a noisy ps pump since the temperature has dipped below freezing