Valve Spring

WARNING: This page is about a different car, the 2002 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.

Measure free length and outer diameter of each valve spring. Also check for damage or deformation.
Inspection standard: Refer to CONTROL VALVE AND PLUG RETURN SPRINGS .
Replace valve springs if deformed or fatigued.

Fig 1: Identifying Valve Spring Free Length
Courtesy of NISSAN MOTOR CO., U.S.A.