Connecting Rod: Service and Repair

Pistons and Connecting Rod Overview

• Lubricate all bearings and running surfaces.





1 Bolts

• Replace

• 50 Nm plus an additional 90° turn

• Lubricate the threads and contact surface

• Use old bolts for radial play measurement, tighten to 50 Nm but do not tighten further

2 Connecting Rod Bearing Cap

• Mark for installation later

3 Bearing Shells

• Check that retaining tabs are secured

• Replace any worn bearing shells

• Radial clearance, measuring, refer to => [ Connecting Rod, Measuring Radial Clearance ] Testing and Inspection

• Oversized bearings are available for reworked crankshaft connecting rod journals.

• The connecting rod tabs are above each other

4 Connecting Rod

• Only replace as set

• Axial play for each new connecting rod pair: 0.20 to 0.45 mm

• Radial clearance, measuring, refer to => [ Connecting Rod, Measuring Radial Clearance ] Testing and Inspection

5 Circlip

• Replace

6 Piston Pin

• If tight, heat piston to 60 °C (140 °F)

• Removing and installing using a pilot drift (VW 222 A)

7 Piston

• Install with piston ring compressor

• Piston and cylinder dimensions, refer to => [ Piston and Cylinder Dimensions ] [1][2]Piston, Engine

8 Piston Rings

• Offset gaps by 120°

• Use piston ring pliers for removing and installing

• Installation position: The "TOP" marking or side with writing faces the piston crown.

Piston Ring Gap, Checking





- Push the piston ring squarely from above down to approximately 15 mm from the bottom end of the cylinder.






Ring to Groove Clearance, Checking





- Clean the piston ring groove before checking.






Pistons, Checking





- Measure approximately 10 mm from the lower edge, at a 90° angle to the piston pin axis using a 75 to 100 mm external micrometer.

• Maximum deviation from nominal dimension: 0.03 mm.

Nominal dimension, refer to => [ Piston and Cylinder Dimensions ] [1][2]Piston, Engine.

Measuring Cylinder Bore





- Using a cylinder gauge (VAS 6078) or inside micrometer set 18-100 mm (US1033/S) measure in a diagonal sequence at 3 positions transversely - A - and longitudinally - B -.

• Maximum deviation from nominal dimension: 0.08 mm.

Nominal dimension, refer to => [ Piston and Cylinder Dimensions ] [1][2]Piston, Engine.

Piston Installed Position






The coating on the piston crown could be destroyed.

• Mark the allocation to the cylinder on the piston crown with paint for installation. Do not mark the piston crown with a punch, notch or similar object.

• Installation position: Arrow on piston face points toward belt pulley side.

Mark Connecting Rod





• Only replace the connecting rods as a set.

- Mark the connecting rod and connector rod bearing caps to each other and to the cylinder - arrow - with paint for installation.

Connecting Rod, Installed Location





• The molded tabs - arrows - on the beveled surfaces of the connecting rod pairs "1 and 2", "3 and 4" and "5 and 6" must face each other.

Oil Spray Jet for Piston Cooling





1. Insert the bolt with locking compound. Tighten to 9 Nm.

2. Oil spray jet with spray nozzle valve


• Do not bend the oil spray nozzles.

• Replace the oil spry nozzles if they are bent.