Piston Ring Clearance Inspection

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2008 Mazda 6, 2007 Mazda 6, 2006 Mazda 6, 2005 Mazda 6, and 2004 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

Measure the piston ring-to-ring groove clearance around the entire circumference.
- If the piston ring-to-ring groove clearance exceeds the maximum clearance, replace the piston and piston ring.
  Standard Clearance
  
  Top: 0.040-0.075 mm {0.0016-0.0029 in}
  
  Second: 0.040-0.085 mm {0.0016-0.0033 in}
  
  Maximum Clearance
  
  0.10 mm {0.0039 in}
  
  Fig 1: Measuring Piston Ring-To-Ring Groove Clearance
  Courtesy of MAZDA MOTORS CORP.
Insert the piston ring into the cylinder by hand and use the piston to push it to the bottom of the ring travel.
Measure each piston ring end gap with a feeler gauge.
- If the piston ring end gap exceeds the maximum end gap, replace the piston ring.

Standard End Gap

Top: 0.10-0.25 mm {0.004-0.009 in}

Second: 0.27-0.42 mm {0.011-0.016 in}

Oil (side Rail): 0.15-0.65 mm {0.006-0.025 in}

Fig 2: Measuring Piston Ring End Gap

Courtesy of MAZDA MOTORS CORP.

Maximum End Gap

Top: 0.50 mm {0.019 in}

Second: 0.65 mm {0.025 in}

Oil (Side Rail): 0.90 mm {0.035 in}