48 98 19 Removing and installing hydraulic pump (Cayenne V6) - as of MY 2004 (Cayenne TIP, Cayenne MAN): General
Damage to the power steering will occur if there is a shortage of oil in the hydraulic system. Even small leaks can cause the hydraulic fluid to escape and damage the servo pump as a result of high oil pressure occurring in the hydraulic circuit.
Grunt-like noises that can be heard when the steering is locked, or foam formation in the reservoir indicate a shortage of oil and/or that air has also been sucked in. Before filling the reservoir, any existing leaks must be eliminated on the suction side. Alternatively, the defective part on the pressure side should be replaced.