Piston Installed Location And Allocation, Piston To Cylinder
WARNING: This page is about a different car, the 2016 Audi A3 and 2015 Audi A3. However, it is still accessible from the selected car via links, so may be relevant.
Courtesy of AUDI OF AMERICA, LLC
-- For the reinstallation of used pistons, mark the allocation to the cylinder on the piston crown with paint.
Arrow on the piston crown facing the pulley side -arrow-.