>>F<< O-Ring Installation
WARNING: This page is about a different car, the 2012 Mitsubishi Lancer. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
Avoid adhesion of engine oil or grease to the O-ring.
Fit the O-ring in the water pump inlet pipe groove, wet the O-ring circumference or the pipe mounting area inner wall, and then insert the O-ring.
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.