C7.1 Marine Engine Caterpillar

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Hot engine components can cause injury from burns. Before performing maintenance on the engine, allow the engine and the components to cool.

Before you begin inspection of the turbocharger, be sure that the inlet air restriction is within the specifications for your engine. Be sure that the exhaust system restriction is within the specifications for your engine. Refer to Systems Operation, Testing, and Adjusting, "Air Inlet and Exhaust System - Inspect".

The condition of the turbocharger will have definite effects on engine performance. Use the following inspections and procedures to determine the condition of the turbocharger.

• Inspection of the compressor and the compressor housing

• Inspection of the turbine wheel and the turbine housing

Specifications

Inspection of the Compressor and the Compressor Housing

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Illustration 1	g03876952
(1) Turbine housing (2) Compressor housing

1. Inspect the compressor wheel for damage from a foreign object. If there is damage, determine the source of the foreign object. Replace the turbocharger. If there is no damage, go to step 2.

2. Turn the rotating assembly by hand. While you turn the assembly, push the assembly sideways. The assembly should turn freely. The compressor wheel should not rub the compressor housing. The turbocharger must be replaced if the compressor wheel rubs the compressor wheel housing. If there is no rubbing or scraping, go to step 3.

3. Inspect the compressor and the compressor wheel housing for oil leakage. An oil leak from the compressor may deposit oil in the aftercooler. If oil is found in the aftercooler, then drain and clean the aftercooler.

   1. Check the oil level in the crankcase. If the oil level is too high, adjust the oil level.

   2. Inspect the engine air cleaner element. Replace a dirty engine air cleaner element with a clean engine air cleaner element. Refer to Operation and Maintenance Manual, "Engine Air Cleaner Element (Single Element) - Replace" for the correct procedure. Inspect the engine air cleaner service indicator. Refer to Operation and Maintenance Manual, "Engine Air Cleaner Service Indicator - Inspect" for the correct procedure.

   3. Inspect the engine crankcase breather. Clean the engine crankcase breather or replace the engine crankcase breather if the engine crankcase breather is plugged.

   4. Remove the pipe for the oil drain. Inspect the drain opening. Inspect the oil drain line. Inspect the area between the bearings of the rotating assembly shaft. Look for the oil sludge. Inspect the oil drain hole for the oil sludge. Inspect the oil drain line for the oil sludge in the drain line. If necessary, clean the oil drain line. Replace the oil drain line if there is any sign of damage to the oil drain line.

   5. If steps 3.a through 3.d did not reveal the source of the oil leakage, the turbocharger has internal damage. Replace the turbocharger.

Inspection of the Turbine Wheel and the Turbine Housing

Remove the air piping from the turbine housing.

1. Inspect the turbine for damage by a foreign object. If there is damage, determine the source of the foreign object. Replace the turbocharger. If there is no damage, go to step 2.

2. Inspect the turbine wheel for the carbon and other foreign material. Inspect turbine housing (1) for carbon and foreign material. Replace the turbocharger, if necessary. If there is no buildup of carbon or foreign material, go to step 3.

3. Turn the rotating assembly by hand. While you turn the assembly, push the assembly sideways. The assembly should turn freely. The turbine wheel should not rub turbine wheel housing (1). Replace the turbocharger if the turbine wheel rubs turbine housing (1). If there is no rubbing or scraping, go to step 4.

4. Inspect the turbine and turbine housing (1) for oil leakage. Inspect the turbine and turbine housing (1) for oil coking. Some oil coking may be cleaned. Heavy oil coking may require replacement of the turbocharger. If the oil is coming from the turbocharger center housing, go to step 4.a.

   1. Remove the pipe for the oil drain. Inspect the drain opening. Inspect the area between the bearings of the rotating assembly shaft. Look for the oil sludge. Inspect the oil drain hole for the oil sludge. Inspect the oil drain line for the oil sludge. If necessary, clean the drain line.

   2. If crankcase pressure is high, or if the oil drain is restricted, pressure in the center housing may be greater than the pressure of turbine housing (1). Oil flow may be forced in the wrong direction and the oil may not drain. Check the crankcase pressure and correct any problems.

   3. If the oil drain line is damaged, replace the oil drain line.

   4. Check the routing of the oil drain line. Eliminate any sharp restrictive bends. Make sure that the oil drain line is not too close to the engine exhaust manifold.

   5. If steps 4.a through 4.d did not reveal the source of the oil leakage, turbocharger (3) has internal damage. Replace the turbocharger.

Check the Wastegate for Proper Operation.

Note: The turbocharger is a nonserviceable item. The pressure for the wastegate can be checked, but not adjusted.

1. Remove the heat shield from the turbocharger. Remove the guard for the wastegate.
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   Illustration 2	g06059317
   (1) Boost Line (2) Wastegate (3) Actuator Rod

2. Remove the boost line (1) from wastegate (2). Connect an air supply to the wastegate that can be measured accurately.

3. Fasten a dial indicator to the turbocharger so that the end of the actuator rod (3) is in contact with the dial indicator. This will measure axial movement of the actuator rod.

4. Slowly apply 2.47 ± 0.01 bar (35.82 ± 0.15 psi) to wastegate (2).

5. The actuator should move 1.23 mm – 1.77 mm (0.05 inch – 0.07 inch). Ensure that the dial indicator returns to zero when the air pressure is released.

6. Repeat the test several times. This will ensure that an accurate reading is obtained.

7. If the operation of wastegate (2) is incorrect then the turbocharger must be renewed.