Turbocharger - Inspection Procedure
88isuzu04BULLETIN NUMBER SB88-01-002
ISSUE DATE June 7, 1988
GROUP ENGINE
C223 TURBOCHARGER INSPECTION
VEHICLES AFFECTED P'UP (KB) and Trooper II (KT) models with C223 turbocharged engine.
SERVICE INFORMATION Many turbochargers that are replaced because of oil leakage, noise or lack of power complaints are later found (during warranty inspection) to have no defects.
All related engine systems must be operating properly in order for the turbocharger to function correctly. This Service Bulletin describes basic engine troubleshooting and turbocharger inspection procedures which must be completed before a turbocharger is replaced.
SERVICE PROCEDURE
1. Verify that the engine air intake, fuel, exhaust, and PCV systems are operating properly, using the inspection procedures in the appropriate Workshop Manual.
2. Turbocharger Exterior and Installation
a. Visually check for:
Missing or loose nuts and bolts.
Loose or damaged intake and exhaust ducting
Damaged oil supply and drain lines
Cracked or deteriorating turbocharger housings
External oil or coolant leakage
b. Correct any installation problems. If any turbocharger parts are damaged, replace turbocharger.
FIGURE 1:
3 . Compressor Wheel and Housing. Refer to Figure 1.
a. Remove the ducting from the compressor inlet.
b. Using a flashlight, check the compressor for wheelto-housing rub, evidence of oil leakage, or foreign object damage.
c. If wheel rub is found, and the attaching hardware is secure, the turbocharger must be replaced.
d. Inspect for oil deposits on the compressor air inlet side. Determine whether the oil has come with the blow-by gas or from the turbocharger center housing.
NOTE Heavy oil deposits on the compressor wheel require turbocharger replacement.
Oil deposits may occur if the engine has been operated at low idle for an extended period of time. In this case, the turbocharger is not defective. However, if the oil deposits are heavy, the turbocharger must be replaced.
- Sludged or burned oil indicate that the oil has seeped past the compressor seal. The turbocharger must be replaced if this condition is evident.
Check whether the oil deposits have resulted from a restricted oil drain line. This condition may be caused by a sludged line or by overfilling the crankcase. Crankcase overfilling will also result in excess oil going through the PCV system and onto the compressor wheel.
e. Oil deposits in the compressor can also be caused by a restricted air intake system. Check for and correct a dirty air cleaner or debris and/or damage in the intake ducting.
f. Replace turbocharger if the wheel has been damaged by a foreign object. Check for loose ducting or debris in the intake system, and for engine damage before installing a new turbocharger.
g. Reinstall compressor inlet ducting.
FIGURE 1:
4. Turbine Wheel and Housing. Refer to Figure 1.
a. Remove the exhaust outlet duct from the turbine inlet.
b. Using a flashlight, check for wheel-to-housing rub or foreign object damage. If wheel rub or foreign object damage to the turbine is visible, the turbocharger must be replaced.
c. Inspect for oil deposits. If oil deposits are found, determine whether the oil has come from the engine exhaust or from the turbocharger center housing.
NOTE Heavy oil deposits on the turbine wheel require turbocharger replacement.
If the oil in the turbine appears to have come from the center housing, inspect the oil deposits on the turbine exhaust outlet side:
- Oil deposits in the turbine may occur if the engine has been operated at low idle for an extended period of time. In this case, the turbocharger is not defective. However, if the oil deposits are heavy, the turbocharger must be replaced.
- Sludged or burned oil indicate that the oil has seeped past the turbine seal. The turbocharger must be replaced if this condition is evident.
Check whether the oil deposits have resulted from a restricted oil drain line. This condition may be caused by a sludged line or by overfilling the crankcase.
d. Reinstall the exhaust outlet duct to the turbine outlet.
Figure 2:
5. Journal Bearings
a. If no damage is visible in the turbine and compressor areas, spin the rotating assembly by hand. It should spin freely with no drag or grinding noises. The wheels should not come into contact with their housings.
b. Inspect for excessive wear of the journal bearings as follows (Figure 2):
Wipe any oil from the inside of the turbocharger compressor housing.
Push the compressor shaft to one side.
Using a feeler gauge, measure the clearance between the compressor wheel blade and housing. Minimum clearance is 0.1 mm.