KIT- 4797553 - Caterpillar

Inspection of the Turbine Wheel and the Turbine Housing
Illustration 2 g00922420
Typical example of a turbocharger
(1) Turbine housing
(2) Turbine wheel
Remove the air piping from the turbine housing.
Inspect turbine wheel (2) 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 3.
Clean turbine wheel (2) and turbine housing (1) if you find buildup of carbon or foreign material. If there is no buildup of carbon or foreign material, go to Step 4.
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 the turbine housing. Replace the turbocharger if the turbine wheel rubs the turbine housing. If there is no rubbing or scraping, go to Step 5.
Inspect the turbine wheel and the turbine housing for oil leakage and 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 5.a. Otherwise go to “Inspection of the Wastegate”.
Remove the oil drain tube. Inspect the oil drain hole and the oil drain tube for oil sludge. Inspect the area between the bearings of the rotating assembly shaft. If necessary, clean the rotating assembly shaft, the oil drain hole, and the oil drain tube.
If crankcase pressure is high, or if the oil drain is restricted, pressure in the center housing may be greater than the pressure of the turbine housing. Oil flow may be forced in the wrong direction and the oil may not drain. Check the crankcase pressure and correct any problems.
If the oil drain tube is damaged, replace the oil drain tube.
Check the routing of the oil drain tube. Eliminate any sharp restrictive bends. Make sure that the oil drain tube is not too close to the engine exhaust manifold.
If Steps 5.a through 5.d did not reveal the source of the oil leakage, the turbocharger has internal damage. Replace the turbocharger. Inspection of the Wastegate
The wastegate controls the amount of exhaust gas that is allowed to bypass the turbine side of the turbocharger. This valve then controls the rpm of the turbocharger.When the engine operates in conditions of low boost (lug), a spring presses against a diaphragm in the canister. The actuating rod will move and the wastegate will close. Then, the turbocharger can operate at maximum performance.When the boost pressure increases against the diaphragm in the canister, the wastegate will open. The rpm of the turbocharger becomes limited. The rpm limitation occurs because a portion of the exhaust gases bypass the turbine wheel of the turbocharger.The following levels of boost pressure indicate a problem with the wastegate:
Too high at full load conditions
Too low at all lug conditions
Table 1
Turbocharger Boost Pressures
Number That Is Stamped On The Turbocharger Boost Pressures
2674A342 145