Radiator Test

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2014 Honda Ridgeline, 2013 Honda Ridgeline, 2012 Honda Ridgeline, 2011 Honda Ridgeline, and 2010 Honda Ridgeline. However, it is still accessible from the selected car via links, so may be relevant.

Wait until the engine is cool, then carefully remove the radiator cap, and fill the radiator with engine coolant to the base of the filler neck.
Attach a commercially available pressure tester (A) to the radiator, and apply a pressure of 93-123 kPa (0.95-1.25 kgf/cm² , 13.5-17.8 psi).

Fig 1: Attaching Available Pressure Tester To Radiator
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Inspect for engine coolant leaks and a drop in pressure.
Remove the tester, then reinstall the radiator cap.