Filter assembly and filter element

A filter element for filtering fluid comprising:

• a cylinder of pleated filter media at least partially surrounding a central axis with radially spaced outer and inner circumferences, and extending between first and second longitudinal ends to define an open central region for fluid passing through the cylinder of pleated filter media in a radial direction;
• a first end cap connected to the first longitudinal end of the cylinder of pleated filter media and defining a fluid flow aperture opening into said open central region, said first end cap including an outer periphery, a plurality of first indexing structures projecting radially beyond said outer periphery, said plurality of first indexing structures comprising a plurality of coplanar rigid supports extending radially outwardly from said outer periphery at locations angularly spaced from each other around said outer periphery of said first end cap;
• and
• an imperforate second end cap connected to the second longitudinal end of the cylinder of pleated filter media, said second end cap closing the second end of the cylinder of pleated filter media and having a shape defined by an outer periphery interrupted by at least one second indexing structure, said at least one second indexing structure comprising a notch extending inwardly from said outer periphery of said closed second end cap past the outer circumference of said cylinder of pleated filter media,
• wherein said first and second indexing structures have a predetermined angular relationship to each other about the central axis and said cylinder of pleated filter media is exposed to fluid flow at said outer circumference between said first and second end caps.