ENGINE AR 6A9733 - Caterpillar

Probable Causes
Engine oil cooler core
Jacket water pump
Auxiliary water pump (if equipped)
Water-cooled turbocharger (if equipped)
Air compressor (if equipped)
Cylinder head gasket
Cylinder head
Cylinder liner
Cylinder blockRecommended Actions
Engine Oil Cooler Core
Check for leaks in the oil cooler core. If a leak is found, install a new oil cooler core. Refer to the Disassembly and Assembly manual.
Drain the crankcase and refill the crankcase with clean engine oil. Install new engine oil filters. Refer to the Operation and Maintenance Manual.Jacket Water Pump
Check the weep hole of the jacket water pump for plugging. A plugged weep hole may cause coolant to be forced past the pump shaft seals into the crankcase. A crack in the pump housing will also allow coolant to contaminate the engine oil. Thoroughly inspect the water pump for damage. If internal leakage is suspected, remove the pump from the engine in order to perform a thorough inspection.Auxiliary water pump (if equipped)
If the application is equipped with an auxiliary water pump, check the weep hole of the pump for plugging. A plugged weep hole may cause coolant to be forced past the pump shaft seals into the crankcase. A crack in the pump housing will also allow coolant to contaminate the engine oil. Thoroughly inspect the pump for damage. If internal leakage is suspected, remove the pump from the engine in order to perform a thorough inspection.Water-Cooled Turbocharger (If Equipped)
In water-cooled turbochargers, the shaft bearings for the turbochargers are lubricated by the engine lubrication system. If a crack develops, there is a potential for water to leak into the lubrication system.Pressurize the cooling system. Thoroughly inspect each of the turbochargers for external leakage and internal leakage. Look for cracks that may have developed in the housings. If a leak is identified, perform the necessary repairs.Air Compressor (If Equipped)
If the application is equipped with an air compressor, consider the unit as a potential leak path for coolant. The air compressor is cooled by the engine cooling system and the air compressor is lubricated by the engine lubrication system. Check the housing of the air compressor for cracks. Refer to the air compressor service literature for troubleshooting information.Cylinder Head Gasket
Remove the cylinder head. Refer to the Disassembly and Assembly manual.
Install a new cylinder head gasket and new water seals in the spacer plate. Refer to the Disassembly and Assembly manual.Cylinder Head
Check for cracks in the cylinder head. If a crack is found, repair the cylinder head and/or replace the cylinder head. Refer to the Disassembly and Assembly manual.Cylinder Liner
Check for cracked cylinder liners. Replace any cracked cylinder liners. Refer to the Disassembly and Assembly manual.Cylinder Block
Inspect the cylinder block for cracks. If a crack is found, repair the cylinder block or replace the cylinder block.