Audi Workshop Service and Repair Manuals > A4 Mk2 > Power unit | 6-cylinder TDI engine (2.7 ltr.; 3.0 ltr. 4-valve common rail), mechanics | Enginecrankshaft group, pistons | Pistons and conrods

Checking piston projection at TDC

Note

t	Piston projection at TDC must be measured when installing new pistons or a short engine. Depending upon piston projection, install the corresponding cylinder head gasket according to the table below:

t	If the measured values for piston projection are not the same for all pistons, use the highest value to determine the correct gasket size.

t	The cylinder head gasket must be determined separately for each cylinder bank.

Special tools and workshop equipment required

t	Measuring bridge -VW 382/7- from measuring tool -VW 382-

t	Measuring plate -VW 385/17- from universal measuring tool -VW 385-

t	Dial gauge -VAS 6079-

Procedure

–	Set up dial gauge -VAS 6079- with measuring bridge -VW 382/7- and measuring plate -VW 385/17-.

–	Measure piston projection at two points -1- for each piston.

Piston projection above top surface of cylinder block	Identification (No. of holes)
0.39 … 0.49 mm	1
0.49 … 0.54 mm	2
0.54 … 0.65 mm	3

Identification of cylinder head gasket

1 -

Holes

2 -

Part No.

Note

The gaskets for the left and right cylinder heads have different shapes and cannot be interchanged.

Audi Workshop Service and Repair Manuals