TUBE AS 4377217 - Caterpillar

Probable Causes
Engine oil cooler
Cylinder head gasket
Cylinder head
Cylinder blockRecommended Actions
Note: The procedures have been listed in order of probability. Complete the procedures in order.
Table 1
Troubleshooting Test Steps Values Results
1. Engine Oil Cooler
A. Drain the engine lubricating oil and coolant from the engine. Check for leaks in the oil cooler assembly.
Refer to Systems Operation, Testing, and Adjusting, "Cooling System" for the correct procedure.
Oil level
Result: Evidence of coolant in the oil system is identified.
Repair: Install a new oil cooler. Refer to Disassembly and Assembly, "Engine Oil Cooler - Remove" and Disassembly and Assembly, "Engine Oil Cooler - Install" for the correct procedure.
Result: No evidence of coolant in the oil system is found.
Proceed to Test Step 2.
2. Cylinder Head Gasket
A. Remove the cylinder head. Refer to Disassembly and Assembly, "Cylinder Head - Remove" for the correct procedure. Inspect the cylinder head gasket for faults and any signs of leakage.
Cylinder head gasket
Result: The cylinder head gasket is faulty or shows signs of leakage.
Repair: Install a new cylinder head gasket.
Result: The cylinder head gasket is OK.
Proceed to Test Step 3.
3. Cylinder Head
A. Check the cylinder head for flatness. Refer to Systems Operation, Testing, and Adjusting, "Cylinder Head - Inspect" for the correct procedure.
B. Check the mating face of the cylinder head for faults and signs of leakage. If a fault is found, replace the cylinder head. If signs of leakage are found, determine the cause of the leakage. Refer to Systems Operation, Testing, and Adjusting, "Cylinder Head - Inspect" for the correct procedure.
C. Check the internal core plugs in the cylinder head for signs of leakage.
Cylinder head
Result: The cylinder head is not within specification for flatness.
Repair: Install a new cylinder head. Refer to Disassembly and Assembly, "Cylinder Head - Install" for the correct procedure.
Result: The cylinder head shows signs of a fault or leakage.
Repair: Install a new cylinder head. Refer to Disassembly and Assembly, "Cylinder Head - Install" for the correct procedure.
Result: An internal core plug in the cylinder head shows signs of leakage.
Repair: Replace the faulty core plug.
Result: The cylinder head is OK.
Proceed to Test Step 4.
4. Cylinder Block
A. Inspect the top face of the cylinder block for faults and signs of leakage.
Cylinder block
Result: The top face of the cylinder block has a fault.
Repair: Replace the cylinder block.
Result: The top face of the cylinder block shows signs of leakage.
Repair: Determine the cause of the leakage. Refer to Systems Operation, Testing, and Adjusting, "Cylinder Block - Inspect" for the correct procedure.
Result: The cylinder block is OK.
Repair: Install the cylinder head. Refer to Disassembly and Assembly, "Cylinder Head - Install".
Remove the oil filter element. Install a new engine oil filter element. Fill the engine with clean engine oil to the correct level. Refer to the Operation and Maintenance Manual, "Engine Oil and Filter - Change" for more information.
Fill the cooling system. Refer to the Operation and Maintenance Manual for more information.
Contact the Dealer Solution Network (DSN).