Water Control Valve: Inspection

WARNING: This page is about a different car, the 2003 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.

Check valve seating condition at ordinary room temperatures. It should seat tightly.
Check valve opening temperature and maximum valve lift.

Fig 1: Valve Opening Temperature Chart
Courtesy of NISSAN MOTOR CO., U.S.A.
Then check if valve closes at 5°C (9°F) below valve opening temperature.

Fig 2: Check Valve Opening Temperature And Maximum Valve Lift
Courtesy of NISSAN MOTOR CO., U.S.A.