In brief
Electrical assistance does not automatically mean the same oil circle.
Useful to know
HELLA offers oil coolers in steering systems with appropriate hydraulic performance. Their task is the removal of heat from the working liquid. [1]
This is not an obligatory part of any power steering vehicle. First, identify what kind of support the particular model has. The word "servo" describes the aid, but does not specify the energy and mechanical path. When comparing parts, use the scheme of the correct system; the transfer of a device from a hydraulic to a purely electrical context creates erroneous expectations.
Sources
For further detail and to check the information: