TACHOMETER-ELECTRIC 3N7288 - Caterpillar

Probable Causes
Engine oil cooler
Power train oil cooler (if equipped)
Water-cooled turbocharger (if equipped)
Cylinder head gasket
Cylinder head
Cylinder blockNote: Verify the presence of oil in the coolant with a scheduled oil sample. Verification must be made before performing the procedure.Recommended Actions
Table 1
Troubleshooting Test Steps Values Results
1. Check for leaks in the Engine Oil Cooler
A. Refer to the Testing and Adjusting manual for additional information.
Oil Cooler
Result: A leak was not found in the engine oil cooler.
Proceed to Test Step 2.
Result: A leak is found in the engine oil cooler.
Repair: Perform the following:
1. Install a new oil cooler core. Refer to the Disassembly and Assembly manual for additional information.
2. Flush the cooling system. Refer to the Operation and Maintenance Manual for additional information.
3. Refill the cooling system with the proper coolant. Refer to the Operation and Maintenance Manual for the correct coolant and capacities.
4. Check the oil for coolant. If coolant is found in the oil, drain the crankcase.
5. 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.
If the problem is not resolved, proceed to Test Step 2.
2. Check for Leaks in the Power Train Oil Cooler
A. Refer to the Testing and Adjusting manual for additional information.
Power Train Oil Cooler
Result: A leak was not found in the power train oil cooler.
Proceed to Test Step 3.
Result: A leak is found in the power train oil cooler.
Repair: Perform the following:
1. Install a new oil cooler core. Refer to the Disassembly and Assembly manual for additional information.
2. Flush the cooling system. Refer to the Operation and Maintenance Manual for additional information.
3. Refill the cooling system with the proper coolant. Refer to the Operation and Maintenance Manual for the correct coolant and capacities.
4. Check the oil for coolant. If coolant is found in the oil, drain the crankcase.
5. 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.
If the problem is not resolved, proceed to Test Step 3.
3. Inspect the Water-Cooled Turbocharger
A. Remove the oil drain line from the turbocharger and pressurize the cooling system, Refer to Testing and Adjusting, "Cooling System - Test" for additional information.
B. Check the turbocharger for coolant leakage.
Turbocharger
Result: The turbocharger is not cracked.
Proceed to Test Step 4.
Result: The turbocharger is cracked.
Repair: Perform the following:
1. Replace the turbocharger. Refer to the Disassembly and Assembly manual for additional information.
2. Flush the cooling system. Refer to the Operation and Maintenance Manual for additional information.
3. Refill the cooling system with the proper coolant. Refer to the Operation and Maintenance Manual for the correct coolant and capacities.
4. Check the oil for coolant. If coolant is found in the oil, drain the crankcase.
5. 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.
If the problem is not resolved, proceed to Test Step 4.
4. Inspect the Cylinder