Radiator Cap Test

WARNING: This page is about a different car, the 2008 Honda Pilot, 2007 Honda Pilot, and 2006 Honda Pilot. However, it is still accessible from the selected car via links, so may be relevant.

Remove the radiator cap (A), wet its seal with engine coolant, then install it on a commercially available pressure tester (B).

Fig 1: Installing Radiator Cap On Pressure Tester
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Apply a pressure of 93-123 kPa (0.95-1.25 kgf/cm² , 14-18 psi).
Check for a drop in pressure.
If the pressure drops, replace the cap.