Piston Ring Inspection

WARNING: This page is about a different car, the 2014 Mitsubishi Outlander. However, it is still accessible from the selected car via links, so may be relevant.

Check the piston ring for damage, excessive wear, and breakage. Replace if defects are evident. If the piston has been replaced with a new one, the piston rings must also be replaced with new ones.
Check for clearance between the piston ring and ring groove. If the limit is exceeded, replace the ring or piston, or both.
Standard value:

Number 1: 0.04 - 0.08 mm (0.0016 - 0.0031 inch)

Number 2: 0.03 - 0.07 mm (0.0012 - 0.0027 inch)

Limit: 0.1 mm (0.004 inch)

Fig 1: Checking Clearance Between Piston Ring And Ring Groove
Insert the piston ring into the cylinder bore. Force the ring down with a piston, the piston crown being in contact with the ring, to correctly position it at right angles to the cylinder wall. Then, measure the end gap with a feeler gauge. If the ring gap is excessive, replace the piston ring.
Standard value:

Number 1: 0.18 - 0.33 mm (0.008 - 0.012 inch)

Number 2: 0.28 - 0.48 mm (0.012 - 0.018 inch)

Oil: 0.10 - 0.60 mm (0.004 - 0.023 inch)

Limit:

Number 1, Number 2: 0.8 mm (0.03 inch)

Oil: 1.0 mm (0.04 inch)

Fig 2: Identifying Piston Ring Gap