ELBOW 4755040 - Caterpillar

Probable Causes
Engine oil cooler
Power train oil cooler (if equipped)
Water-cooled turbocharger
Cylinder head gasket
Cylinder head
Cylinder blockVerify the presence of oil in the coolant with a scheduled oil sample. Verification must be made before performing the procedure.Recommended Actions
Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.
Table 1
Troubleshooting Test Steps Values Results
1. Check for leaks in the Engine Oil Cooler
Refer to Testing and Adjusting for the proper procedure.
Oil Cooler
Result: A leak is found in the engine oil cooler.
Repair: Install a new oil cooler core. Refer to the Disassembly and Assembly manual.
Flush the cooling system. Refer to the Operation and Maintenance Manual for the proper flushing procedure. Refill the cooling system with the proper coolant. Refer to the Operation and Maintenance Manual for the correct coolant and capacities.
Check the oil for coolant. If coolant is found in the oil, drain the crankcase. Refill the crankcase with the proper oil after the leak has been repaired. Refer to the Operation and Maintenance Manual for the correct oil capacities and viscosity.
Verify that the repair eliminated the problem.
Result: A leak was not found in the engine oil cooler.
Proceed to Test Step 2.
2. Check for Leaks in the Power Train Oil Cooler
Refer to Testing and Adjusting for the proper procedure.
Power Train Cooler
Result: A leak is found in the power train oil cooler.
Repair: Install a new oil cooler core. Refer to the Disassembly and Assembly manual.
Flush the cooling system. Refer to the Operation and Maintenance Manual for the proper flushing procedure. Refill the cooling system with the proper coolant. Refer to the Operation and Maintenance Manual for the correct coolant and capacities.
Check the oil for coolant. If coolant is found in the oil, drain the crankcase. Refill the oil after the leak has been repaired. Refer to the Operation and Maintenance Manual for the correct oil capacities and viscosity.
Verify that the repair eliminated the problem.
Result: A leak was not found in the power train oil cooler.
Proceed to Test Step 3.
3. Inspect Water-Cooled Turbocharger (if equipped)
A. Remove the oil drain line from the turbo and pressurize the cooling system, Refer to Testing and Adjusting, "Cooling System - Test".
B. Check the turbocharger for coolant leakage.
Turbocharger
Result: The turbocharger is cracked.
Repair: Replace the turbocharger. Refer to the engine Disassembly and Assembly for the correct procedure.
Flush the cooling system, Refer to the Operation and Maintenance Manual for the correct procedure.
Refill the cooling system with the proper coolant. Refer to the Operation and Maintenance Manual for the correct coolant and capacities.
Check the oil for coolant. If coolant is found in the oil, drain the oil. Refill the oil after the leak has been repaired. Refer to the Operation and Maintenance Manual for the correct oil capacities.
Verify that the repair eliminated the problem.
Result: The turbocharger is not cracked.
Proceed to Test Step 4.
4. Inspect the Cylinder Head Gasket
A. Remove the cylinder head. Refer to the Disassembly and Assembly manual.
B. Check the cylinder liner projection. Refer to the Systems Operation/Testing and Adjusting manual.
C. Install a