Pistons, Checking

WARNING: This page is about a different car, the 2023 Volkswagen Atlas. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Checking Piston Bore

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Special tools and workshop equipment required

Outside Micrometer - 75-100mm:VAS 6071

-- Measure approximately 15 mm in from the lower edge at a 90° angle to the piston pin axis using a micrometer.

Deviation from specified size: maximum 0.04 mm

		Piston diameter
Standard dimension	mm	82.42 ¹⁾
¹⁾ Measurements without graphite coating (thickness = 0.02 mm). The graphite coating wears off.

Piston Ring Gap, Checking

Fig 2: Checking Piston Ring Gap

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Push the ring squarely to the cylinder wall from above down in the lower cylinder opening approximately 15 mm from bottom edge of the cylinder. To push in use a piston without rings.

Piston ring gap	New	Wear limit
1. Compression ring	0.30 to 0.40 mm	0.60 mm
2. Compression ring	0.40 to 0.50 mm	0.70 mm
Oil Scraping Ring	cannot be measured	cannot be measured

Piston Ring Groove Clearance, Checking

Fig 3: Checking Piston Ring Groove Clearance

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Clean the piston ring groove before checking.

Piston ring height clearance	New	Wear limit
1. Compression ring	cannot be measured
2. Compression ring	cannot be measured
Oil scraping rings	cannot be measured