ROLLER & BEARING AS 6Y0891 - Caterpillar

Probable Causes
Faulty accessory
Cylinder head and related components
Gear train
Crankshaft and related components
PistonRecommended Repairs
Table 1
Troubleshooting Test Steps Values Results
1. Faulty Accessory
A.Isolate the source of the noise from the engine.
B. Remove the suspect engine accessories and inspect.
Accessory
Result: The engine accessories are properly working.
Proceed to Test Step 2.
Result: The engine accessories are not properly working.
Repair: Replace and/or repair the engine accessories.
If the problem is not resolved, proceed to Test Step 2.
2. Cylinder Head and Related Components
A. Inspect the components of the valve train for any damage.
B. Check for signs of damage and/or wear to the:
- Valves
- Cylinder head gasket
- Springs
- Lifters
- Pushrods
Inspect the condition of the camshaft. If a camshaft is replaced, new valve lifters must be install.
Engine Components
Result: There are no damaged engine components.
Proceed to Test Step 3.
Result: There is damaged engine components.
Repair: Repair and/or replace any damaged components and return to service.
If the problem is not resolved, proceed to Test Step 3.
3. Gear Train and Low End Components
A. Inspect the gear train and lower end components.
Gear Train
Result: The gear train and/or lower end components are not damaged.
Proceed to Test Step 4.
Result: The gear train and/or lower end components are damaged.
Repair: Repair or replace any damaged components and return to service.
If the problem is not resolved, proceed to Test Step 4.
4. Crankshaft
A. Inspect the crankshaft and the related components. Look for worn thrust plates and wear on the crankshaft.
B. Inspect the connecting rod bearings and the bearing surfaces on the crankshaft. Make sure that the bearings are in the correct position.
C. Check the counterweight bolts.
Crankshaft
Result: The crankshaft or the related components are not damaged or worn.
Proceed to Test Step 5.
Result: The crankshaft or the related components are damaged or worn.
Repair: Repair or replace any damaged parts and return to service.
If the problem is not resolved, proceed to Test Step 5.
5. Pistons
A. Inspect the piston for damage and wear.
Pistons
Result: The pistons are NOT OK.
Repair: Repair or replace damaged pistons.
Verify that the repair eliminated the problem.
If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).