TURBO GP-BASIC 10R8250 - Caterpillar

Inspection of the Turbine Wheel and the Turbine Housing
Remove the air piping from the turbine outlet casing.
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.
Inspect the turbine wheel for buildup of carbon and other foreign material. Inspect the turbine housing for buildup of carbon and foreign material. Clean the turbine wheel and clean the turbine housing if you find buildup of carbon or foreign material. If there is no buildup of carbon or foreign material, go to Step 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 the turbine wheel housing. Replace the turbocharger if the turbine wheel rubs the turbine wheel housing. If there is no rubbing or scraping, go to Step 4.
Inspect the turbine and the turbine wheel housing for oil leakage. Inspect the turbine and the turbine wheel housing 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. Otherwise go to “Inspection of the Wastegate”.
Remove the oil drain line of the turbocharger . Inspect the drain opening. Inspect the area between the bearings of the rotating assembly shaft. Look for oil sludge. Inspect the oil drain hole for oil sludge. Inspect the oil drain line for oil sludge. If necessary, clean the rotating assembly shaft. If necessary, clean the drain opening. If necessary, clean the drain line.
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 line is damaged, replace the oil drain line.
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.
If Steps 4.a through 4.d did not reveal the source of the oil leakage, the turbocharger has internal damage. Replace the turbocharger. Inspection of the Wastegate
The turbocharger senses boost pressure which actuates the wastegate valve. The wastegate valve controls the amount of exhaust gas that is allowed to bypass the turbine side of the turbocharger. Regulating the amount of exhaust gas that enters the turbocharger regulates the rpm of the turbocharger.
Illustration 1 g00295815
Typical Example
(1) Actuating Rod
(2) Canister
(3) Line When the engine operates in conditions of low boost (lug), a spring presses against a diaphragm in canister (2). This moves actuating rod (1) in order to close the wastegate valve. Then, the turbocharger can operate at maximum performance.As the boost pressure increases against the diaphragm in canister (2), the wastegate valve opens. The rpm of the turbocharger becomes limited. This