Cummins ISX11.9 CM2250 – 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.

Inspect for loose clamps or damage between the intake air piping, air cleaner, turbocharger, charge-air cooler, and intake manifold.

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.

Replace any damaged pipes and tighten any loose clamps.

Excessive back pressure can cause exhaust leaks. Verify the exhaust back pressure is within specified limits. Refer to Procedure 011-009 in Section 11.

Operate the engine at full throttle and maximum load, and check for air leaks. Listen for a whistling noise caused by high-pressure air leaks.

CAUTION  Do not use air tools to remove or install the nut on the V-band clamp. Use of these tools can seriously damage the threads or the bolt and cause the clamp to not be able to be reused.

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

• Turbocharger to charge-air cooler elbow connection
• Inspect the connection and o-ring for damage.
• Tighten the V-band clamps.

• Any charge-air cooler piping or connecting hose.
• Inspect the hose and piping for damage.
• Tighten the hose clamps.

• Check for soot streaks from the turbocharger-to-exhaust manifold mounting gasket.
• Inspect for signs of leakage, such as soot streaks which may appear yellowish, brown, or black. If signs of leakage are present, replace the turbocharger mounting gasket. Refer to Procedure 010-033 in Section 10.

WARNING  Removing the turbine housing V-band tamper-proofing on any variable geometry turbocharger will void the Cummins Inc. warranty coverage.

• Variable geometry turbocharger – turbine housing sealing surface air leak.

For variable geometry turbochargers, the turbine V-band nut has a tamper-proof clamp. Therefore the torque specification for the turbine V-band can not be checked.

The purpose of the tamper-proofing is to prevent disturbing this joint. Any loosening of the V-band or adjusting of the orientation of the turbine housing will affect the sliding nozzle clearances and will damage the turbocharger and result in poor performance.

Indications of leakage are soot streaks from the joint and/or an audible whistle from the engine. The turbocharger must be replaced if there are any indications of leakage from the turbine housing V-band joint.

• Compressor housing sealing surface air leak.
• Tighten the V-band.

• Check for an air leak.
• If an air leak is still present, remove and replace the turbocharger. Refer to Procedure 010-033 in Section 10.

• Check for soot streaks from the exhaust manifold slip joints and exhaust manifold gasket.
• Inspect for signs of leakage, such as soot streaks which may appear yellowish, brown, or black. If signs of leakage are present, replace the slip joints or exhaust manifold gaskets. Refer to Procedure 011-007 in Section 11.

• Check for leakage from the Exhaust Gas Recirculation (EGR) cooler bellow.
• Inspect for signs of leakage such as soot streaks. If signs of leakage are present, replace the EGR cooler bellows or seals. Refer to Procedure 011-024 in Section 11.

• Check for soot streaks from the rear EGR connection tube.
• Tighten the V-band clamp. Refer to Procedure 011-069 in Section 11.
• Check for an exhaust leak. If an exhaust leak is still present, remove and replace the rear EGR connection tube o-ring.

• Check for soot streaks from the EGR hose.
• If an exhaust leak is present from the EGR hose, tighten the hose clamps. Refer to Procedure 011-069 in Section 11.

• Check for soot streaks from the EGR valve o-ring.
• Inspect for signs of leakage such as soot streaks. If signs of leakage are present, replace the EGR valve o-ring. Refer to Procedure 011-022 in Section 11.

• Check for leakage from the EGR valve weep hole.
• Soot leakage at the EGR valve weep hole is normal and is expected. Do not replace the EGR valve if soot streaks are found at the EGR valve weep hole.

• Check for soot leakage at the EGR mass measurement flow assembly and EGR differential pressure sensor.
• Inspect for signs of leakage such as soot streaks which may appear yellowish, brown, or black. If signs of leakage are present, replace the EGR mass measurement flow assembly o-rings. Refer to Procedure 011-066 in Section 11. Replace the EGR differential pressure sensor. Refer to Procedure 019-370 in Section 19.

• Check for soot leakage at the exhaust transfer connection elbow and EGR crossover tube.
• Inspect for signs of leakage such as soot streaks which may appear yellowish, brown, or black. If signs of leakage are present, replace the EGR crossover tube press in place seals. If signs of leakage are present coming from the hose section in the EGR crossover tube, the crossover tube must be replaced. Refer to Procedure 011-070 in Section 11.

• Check the aftertreatment adapter pipe.
• Inspect for visible soot streaks at the V-band joint.
• If soot streaks are found, tighten the V-band clamp. Refer to Procedure 011-043 in Section 11.
• Operate the engine at full throttle and check for leakage at full throttle condition.
• If a leak is still present, remove and replace the gasket with a new gasket and a new V-band clamp.

• Check the aftertreatment inlet connection.
• Inspect for visible soot streaks at the Torca™ clamp or V-band clamp joint. Also inspect for loose or damaged insulation wrapping (if applicable).
• If soot streaks are found, tighten the V-band or Torca™ clamp. Refer to Procedure 011-041 in Section 11.
• Operate the engine at full throttle and check for leakage at full throttle condition.
• If a leak is still present, remove and replace the clamp with a new Torca™ clamp or V-band clamp.

• Check the catalyst to aftertreatment particulate trap connection.
• Inspect for visible soot streaks at the V-band joint.
• If soot streaks are found, check for fault codes relating to high differential pressure in the aftertreatment system. If no fault codes are found, tighten the V-band clamp. Refer to Procedure 011-049 in Section 11.
• Operate the engine at full throttle and check for leakage at full throttle condition.
• If a leak is still present, remove and replace the gasket with a new gasket and V-band clamp.

• Check the aftertreatment diesel particulate filter to outlet connection.
• Inspect for visible soot streaks at the V-band joint.
• If soot streaks are found, check for fault codes relating to high differential pressure in the aftertreatment system. If no fault codes are found, tighten the V-band clamp. Refer to Procedure 011-041 in Section 11.
• Operate the engine at full throttle and check for leakage at full throttle condition.
• If a leak is still present, remove and replace with a new gasket and V-band clamp.

• Check the aftertreatment outlet connection.
• Inspect for visible soot streaks at the V-band joint.
• If soot streaks are found, check for fault codes relating to high differential pressure in the aftertreatment system. If no fault codes are found, tighten the V-band clamp. Refer to Procedure 011-041 in Section 11.
• Operate the engine at full throttle and check for leakage at full throttle condition.
• If a leak is still present, remove and replace with a new gasket and V-band clamp.

• Check the aftertreatment diesel particulate filter differential pressure sensor tube connections.
• Inspect for visible soot streaks at the threaded bosses or hose connections.
• If soot streaks are found at the threaded boss, loosen the differential pressure sensor tube nut, apply a coating of anti-seize compound, and tighten the differential pressure sensor tube nut. Refer to Procedure 011-047 in Section 11.
• If soot streaks are found at the hose connections, remove and connect the hose. Refer to Procedure 011-047 in Section 11.
• Operate the engine at full throttle and check for leakage at full throttle condition.
• If a leak is still present at the threaded boss, remove and replace the differential pressure sensor tube.
• If a leak is still present at the hose connection, replace the differential pressure sensor tube or differential pressure sensor, depending on which component to which hose is permanently attached.
• If damage resulted in coolant, oil, excessive fuel or excessive black smoke entering the exhaust system, the aftertreatment system must be inspected. Refer to Procedure 014-013 in Section 14.

• Check the aftertreatment decomposition pipe and its related components connecting the diesel particulate filter to the selective catalytic reduction (SCR) catalyst.
• Inspect for visible soot streaks at the Torca™ clamp or V-band clamp joint. Also inspect for loose or damaged insulation wrapping (if applicable).
• If soot streaks are found, tighten the V-band or Torca™ clamp. Refer to Procedure 011-062 in Section 11.
• Operate the engine at full throttle and check for leakage at full throttle condition.
• If a leak is still present, remove and replace the clamp with a new Torca™ clamp or V-band clamp.

• Check the aftertreatment SCR catalyst inlet connection.
• Inspect for visible soot streaks at the Torca™ clamp or V-band clamp joint. Also inspect for loose or damaged insulation wrapping (if applicable).
• If soot streaks are found, tighten the V-band or Torca™ clamp.Refer to Procedure 011-036 in Section 11.
• Operate the engine at full throttle and check for leakage at full throttle condition.
• If a leak is still present, remove and replace the clamp with a new Torca™ clamp or V-band clamp.

• Inspect the aftertreatment SCR catalyst for:
• Excessive corrosion
• Damage to the body of exhaust catalyst, i.e. splits or cracks to the body of the exhaust catalyst or connecting pipework.
• Inspect the exhaust catalyst for signs of catalyst solution leaks.
• Check the aftertreatment SCR catalyst weld seam.
• Inspect for visible soot streaks at the weld seam on the aftertreatment SCR catalyst.
• If soot streaks are found, make sure the source of the leak is at the weld seam. If so, the aftertreatment SCR catalyst must be replaced.

• Check the aftertreatment SCR catalyst outlet connection.
• Inspect for visible soot streaks at the V-band joint.
• If soot streaks are found, check for fault codes relating to high differential pressure in the aftertreatment SCR catalyst system. If no fault codes are found, tighten the V-band clamp.
• Operate the engine at full throttle and check for leakage at full throttle condition.
• If a leak is still present, remove the gasket and V-band clamp and replace with new parts.

• Check the aftertreatment SCR catalyst inlet and outlet temperature sensors connections.
• Inspect for visible soot streaks at the threaded bosses or hose connections.
• If soot streaks are found at the threaded boss, loosen the differential temperature sensor tube nut, apply a coating of anti-seize compound, and tighten the differential temperature sensor tube nut.
• If soot streaks are found at the hose connections, remove and connect the hose.
• Operate the engine at full throttle and check for leakage at full throttle condition.
• If a leak is still present at the threaded boss, remove and replace the differential temperature sensor tube.
• If a leak is still present at the hose connection, replace the differential temperature sensor tube.