11 12 729 Checking cylinder head for water leaks (N18)

Special tools required:

Necessary preliminary tasks:

Extend special tool 11 9 521 with special tool 11 9 523 .

Installation note:

Assembly special tool 11 9 521 so that all water channels are sealed.

Fig 1: Sealing Water Ducts Using Special Tool (11 9 521)

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Fix special tool 11 9 523 by tightening to 25 Nm.

Fig 2: Securing Bolts (11 9 523)

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IMPORTANT: For the N18 engine, the special tool 11 9 522 must be modified.

Dimension (A) 15 mm, dimension (B) 79.85 mm.

Both dimensions have to be transferred to special tool 11 9 522 .

Using a suitable tool, cut off the top corner along the dotted line.

Fig 3: Identifying Special Tool Modification Dimensions

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Screw special tool 11 9 522 into place with existing screws (1 and 3) of coolant thermostat.

Sealing flange must rest flat.

NOTE: Compressed air on valve (2) maximum 3 bar .

Heat cylinder head to 60 °.

Visual inspection in a water bath.

Illustration shows (N12).

Fig 4: Screws, Valve And Special Tool (11 9 522)

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Assemble engine.