A4 Quattro Wagon L4-1.8L Turbo (ATW) (2000)
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Before checking, clean ring groove.
Fig. 3 Checking piston diameter
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Measure approximately 10 mm (3/8 inch) from bottom edge, at points offset by 90 from piston pin axis.
Deviation from nominal size: maximum 0.04 mm (0.0016 inch)