Inspecting the Turbocharger for Exhaust Leaks{1052} Caterpillar

Engine:

3512B (S/N: 3ZW1-UP; PWG1-UP; S2M1-UP; 7HM1-UP)

Introduction

Do not perform any procedure in this Special Instruction until you read this information and you understand this information.

Some turbochargers have an accumulation of soot around the joint between the cartridge and the turbine housing. The source of the exhaust leak may not be apparent. Use the inspection procedure in this Special Instruction to determine the source. This enables identification of the correct replacement parts.

Removal of the Turbocharger

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Improper lift rigging can allow unit to tumble causing injury and damage.

Remove the turbocharger from the engine as a complete assembly. Refer to Disassembly and Assembly, SENR6564, "Turbocharger - Remove - Center Mounted Turbocharger" or Disassembly and Assembly, SENR6564, "Turbocharger - Remove - Rear Mounted Turbocharger".

Note: Ensure that the joint between the center housing and the turbine is not disturbed when the turbocharger is removed. This will maintain the deposits of soot that will be present if the turbocharger is leaking.

Initial Inspection

Illustration 1	g01222988
Bearing housing (typical example) (1) Deposits of soot

Illustration 2	g01233203
Compressor housing (typical example) (1) Deposits of soot

Look for signs of possible exhaust leaks at the joint between the turbine housing and the turbocharger cartridge. Inspect the compressor housing and the bearing housing for exhaust soot. Deposits of soot on the compressor housing or on the bearing housing does not mean that the joint is leaking.

Inspection of the Flange for the Turbine Inlet

Illustration 3	g01225434
Joint that is not leaking (1) Clean sealing surface

Inspect the flange for the turbine inlet for cracks and/or exhaust soot. Verify that any soot that is present does not pass through the sealing surface. Deposits of soot that pass through the sealing surface are evidence of a leak.

Illustration 4	g01225479
Typical example (2) Deposits of soot

Removal of the Turbine Housing from the Cartridge

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Improper lift rigging can allow unit to tumble causing injury and damage.

1. Lift the turbocharger and place the turbine housing on a work bench.

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Illustration 5	g01225495

2. Loosen all of the bolts that secure the clamp plates. A modified thin box wrench may need to be used to loosen all of the bolts.

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Illustration 6	g01225492

3. Loosen all of the bolts. Lift the turbocharger 100 mm (4 inch) with a hoist. Refer to Illustration 6.

4. Tap all the way around the turbine housing with a dead blow hammer.

5. Repeat Step 4 until the turbine housing drops straight down from the cartridge.

   Note: Ensure that the turbine housing does not rotate. The relationship of the turbine housing and the cartridge must not change. This will maintain any deposits of soot that may be present.

Note: Some of the bolts that secure the turbine housing to the cartridge may break during this procedure. This is common, especially if the turbocharger has been in service for an extended period of time.

Inspection of the Sealing Joint for the Turbine

Illustration 7	g01226755
Typical example (1) Sealing surface

Inspect the entire sealing surface (1) of the cartridge. The joint was not leaking if the entire sealing surface is free from soot. Refer to Illustration 7. The joint is leaking if a deposit runs through the sealing surface.

Inspection of the Clamp Plates

Illustration 8	g01233372
Typical example of clamp plates (1) Bolt holes

Refer to Illustration 8. Inspect the clamp plates for deposits of soot or for the accumulation of soot. An exhaust leak in this area usually appears between bolt holes (1) .

Ensure that the clamp plates are 6 mm (0.2362 inch) thick. If the clamp plates are not 6 mm (0.2362 inch) thick, discard the original clamp plates and obtain the latest replacement parts. Longer bolts will also be needed.

Inspection of the Turbine Housing

Illustration 9	g01302774
Typical example (1) Sealing surface (2) Bolt hole

Illustration 10	g01302776
(3) Breakthrough of bolt hole (2)

Inspect bolt hole (2). Inspect the inlet of the turbine housing.

On most turbochargers, the joint for the turbine housing is metal to metal. Some turbochargers will have a C-ring seal at this joint. Inspect the turbine housing for any deposits of soot that run through the shoulder of the sealing surface. Refer to Illustration 9.

If a leak is found at the joint between the turbine housing and the cartridge, replace the housing with current available parts. If bolt hole (2) has broken through into the inlet of the turbine housing, replace the housing with current available parts.

If no leaks are found, reassemble the turbocharger. Install a new C-ring seal. Install the 6 mm (0.2362 inch) clamp plates. If the original clamp plates were 3 mm (0.1181 inch) thick, use longer bolts for the assembly. Reinstall the turbocharger.