Connecting Rod: Service and Repair

Pistons and Connecting Rod Assembly Overview

• Oil injector jet for piston cooling => [ Oil spray jet for piston cooling ]






1 Bolts

• Replace

• Lubricate threads and contact surface

• 30 Nm plus an additional 90° turn

2 Connecting rod bearing cap

• Mark for re-installation

• Mark allocation to cylinder with paint - B - => [ Mark connecting rod ]

• When installing bearing cap, observe: The wide thrust flange - A - must point to the same side on connecting rod and connecting rod bearing cap

• Installation position of connecting rod pairs => [ Connecting rod installation position ]

3 Bearing shell

• Check that retaining tabs are secured

• Mark used bearing shells for reinstallation but not on the running surface

• Replace bearing shells that have worn down to the base layer

4 Connecting rod

• Only replace as set

• Mark allocation to cylinder with paint - B - => [ Mark connecting rod ]

• When installing bearing cap, observe: The wide thrust flange - A - must point to the same side on connecting rod and connecting rod bearing cap

• Installation position of connecting rod pairs => [ Connecting rod installation position ]

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

5 Piston pin

• Heat piston to 60 °C if it is difficult to move.

• Removing and installing using a Drift (VW 222 A)

6 Circlip

• Replace

7 Piston

• Mark the installation position and cylinder allocation => [ Piston installed position ]

• Arrow on piston face points toward belt pulley side

• Checking, refer to => [ Pistons, Checking ] Testing and Inspection

• Replace the piston if there are cracks on the piston head or piston shaft

• Install with piston ring compressor

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

• Measuring cylinder bore, refer to => [ Cylinder Bore, Measuring ] Testing and Inspection

8 Piston rings

• Offset gaps by 120°

• Use piston ring pliers for removal and installation

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

• Gap, measuring, refer to => [ Piston Ring Gap, Measuring ] Piston Ring Gap, Measuring

• Measuring side clearance, refer to => [ Ring to Groove Clearance, Measuring ] Ring to Groove Clearance, Measuring

Piston installed position






The coating on the piston crown could be destroyed.

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

Installation position:

• The arrows on the piston heads point to the 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 installation position





• 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 and tighten to 9 Nm; locking compound.

2. Oil spray nozzle with spray nozzle valve (opening pressure 2 to 2.4 bar)

• Do not bend the oil spray nozzles.

• Replace the oil spray nozzles if they are bent.