Inspection of the Rear of the Engine on Certain C3.3, C4.4, and C7.1 Engines {1161, 1201} Caterpillar

Problem

There have been some instances of reported Rear End Oil Seal (REOS) leaks. The reported issue data does not provide enough information to identify the area of the leak and the type of leaking fluid.

Most reported leaks are on engines equipped with a 232-7449 Housing As and a 298-5085 Cylinder Block Gp.

Solution

Illustration 1	g06017061

Rear end oil leaks may originate from many different sources such as the following :

• REOS (1)

• Oil rail plug (2)

• Camshaft plug (3)

• Bridge piece (4)

Illustration 2	g06017560

The leak may also be a water or coolant. Staining from engine preservative may also give the appearance of a leak. See Illustration 2.

Perform the following procedure to troubleshoot the leak and provide the data required to identify the root cause of the leaks.

1. Clean the area of the engine affected by the leaking fluid.

2. Add an Ultraviolet (UV) fluorescent dye to the engine oil. Follow the dilution instructions provided by the manufacturer of the dye. Too much dye can cause permanent staining of the surfaces.

3. Operate the engine until the suspected leak appears again. Stop the engine.

4. Using UV light, and in dark ambient conditions, inspect the area of the leak. Confirm the nature of the leak.

   Note: UV sensitive dye will have a high intensity fluorescence. Some low intensity natural fluorescence may be visible for other fluids.

5. Record the leak with photographs.

6. If the leak is visible but does not show high intensity fluorescence, investigate the source of the leak as the leak is not engine oil.

If the leak is identified as engine oil, perform the following procedure to identify the origin of the leak:

1. Perform a visual inspection of the REOS area. Record with photographs.
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   Illustration 3	g06017610

2. Use the UV light to identify the leak location (see Illustration 3):

   • (A) Between the rotary seal and the crankshaft or between the rotary seal and the seal housing

   • (B) Through the bolt holes

   • (C) Between the static seal and the mating component

3. Raise a Dealer Solutions Network (DSN) ticket including photographs showing the engine oil leak and the origin of the leak.

4. Carefully clean the area around the seal and check for the following faults:

   • Paint Overspray

   • Installation errors

   • Loose bolts

   Record any other observations.

Request field-follow support or perform the following procedure:

1. If possible, rotate the crankshaft and measure the crank palm run-out.

2. Perform the following steps to check for seal-to shaft misalignment (see Illustration 4):
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   Illustration 4	g06017684

   1. Install Tooling (A) to the crankshaft.

   2. Install Tooling (C) as shown in Illustration 4 with the probe in contact with the seal housing at position (X).

   3. Rotate the crankshaft.

   4. Record the minimum and maximum readings from Tooling (C).

   5. Record the total indicated reading.

3. Measure and record the bolt torques for the REOS and the engine oil pan.

4. Remove the REOS and inspect the crank palm. Look for any of the following:

   • Poor surface finish

   • Machining lead

   • Pitting

   • Scratches

   • Corrosion

   • Discoloration

   • Oil deposits

   • Excessive wear

   • Uneven wear (record the minimum and maximum width of the crank palm)

   • Paint

   • Damage

   Record any of the above issues with photographs.

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   Illustration 5	g06018292

5. Inspect REOS primary seal (5) for the following faults:

   • Uneven wear

   • Excessive wear

   • Deposits in the ridges of the seal

   • Scratches

   • Damage

   • Spring retention of the seal

   • Contamination

   Record any of the above issues with photographs.

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   Illustration 6	g06018299

6. Inspect dust seal (6) on the REOS for the following faults:

   • Excessive dust or dirt

   • Excessive wear

   • Damage

   Record any of the above issues with photographs.

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   Illustration 7	g06018307

7. Inspect static seal (7) for the following faults:

   • Excessive surface roughness

   • Scratches

   • Uneven surface

   • Contamination

   • Corrosion

   • Indentations on seal (7) where the seal mates with the bridge piece.

   Record any of the above issues with photographs.

8. Install a new 232-7449 Housing As. Refer to Disassembly and Assembly, Crankshaft Rear Seal - Install for the correct procedure.