M11 Series – Service Manual – 010-024   Air Leaks, Air Intake and Exhaust Systems

CAUTION  Engine intake air must be filtered to prevent dirt and debris from entering the engine. If intake air piping is damaged or loose, unfiltered air will enter the engine and cause premature wear.

Replace damaged pipes and tighten loose clamps as necessary to make sure the air intake system does not leak.

Check for corrosion of the intake system piping under the clamps and hoses. Corrosion can allow corrosive products and dirt to enter the intake system. Disassemble and clean as required.

Operate the engine at high idle, and use a solution of soapy water to spot intake air leaks.

If an air leak exists, the soap bubbles will be drawn in with the air.

Operate the engine at full throttle and rated rpm with maximum load.

Listen for a high-pitched whistling noise from the turbocharger near piping and connections.

The noise can be caused by an air leak from the:

• Turbocharger to discharge elbow connection

Inspect for damage. Tighten loose clamps.

• any charge air cooler tubing or connecting hoses

Inspect the hose and tubing for damage.

Tighten the hose clamps.

Refer to the manufacturer’s specifications for the correct torque value.

• rocker housing and intake manifold gaskets

Inspect the intake manifold and rocker housing to cylinder head gasket joint. Replace the gasket if leaks are found. Refer to Procedure 003-013

• Turbocharger to exhaust manifold mounting gasket

Replace the gasket. Refer to Procedure 010-033 for turbocharger removal and installation.

• Turbine housing sealing surface exhaust leak

Tighten the turbine housing capscrews or v-band clamps.

• Compressor housing sealing surface air leak.

Tighten the compressor housing v-band clamp nut.

Operate the engine at full throttle and rated rpm with maximum load.

Listen again for leaks.

Replace the turbocharger if the air piping is not damaged and the noise can still be heard. Refer to Procedure 010-033.