816385 1 Mercury MOUNT, Upper

System Response:The event code will be logged.Possible Performance Effect:E539-1 (Warning)NoneE539-2 (Derate)The engine power will be derated.TroubleshootingIntake manifold air temperature can be high for the following reasons:
Engine's cooling system
High ambient air temperature
High inlet air restriction and/or high altitude
Restriction in the exhaust system
Faulty inlet air temperature sensor and/or circuitTest Step 1. Perform the following Inspections
Check for Cooling System Problems
Verify that the cooling system is filled to the proper level. If the coolant level is too low, air will get into the cooling system. Air in the cooling system may cause cavitation. This will cause a reduction in coolant flow which can damage a cooling system.
Check the quality of the coolant. Follow the recommendations in the Operation and Maintenance Manual.
Check for adequate coolant flow through the radiator. Check the inlet temperature of the coolant at the radiator inlet. Compare the reading to the regulated temperature. If the temperature is OK, check the outlet temperature of the coolant at the radiator outlet. A high temperature differential indicates an insufficient flow rate.
Check for air in the cooling system. Air can enter the cooling system in different ways. The most common causes of air in the cooling system are the incorrect filling of the cooling system and combustion gas leakage into the cooling system. Combustion gas can get into the system through a cracked cylinder liner, damaged cylinder liner seals, a cracked cylinder head, or a damaged cylinder head gasket.
Check the cooling system hoses and clamps. Damaged hoses with leaks can normally be seen. Hoses that have no visual leaks can soften during operation. The soft areas of the hose can become kinked during operation. These areas can also collapse during operation. These areas of the hose can restrict the coolant flow. Hoses become soft and/or get cracks after a period of time. The inside of a hose can deteriorate, and the loose particles of the hose can restrict the coolant flow.
If a sea water strainer is used in the application, verify that the sea water strainer is not plugged.
Check the heat exchanger for a restriction to the flow of water.
Check the water pump. A water pump with a damaged impeller does not pump enough coolant. Remove the water pump and check for damage to the impeller.
Check the water temperature regulator. A water temperature regulator that does not open, or a water temperature regulator that only opens part of the way can cause overheating.
If the cooling system is equipped with an expansion tank, check the shunt line for the expansion tank. The shunt line must remain submerged in the coolant for proper operation. A restriction of the shunt line from the expansion tank to the inlet of the jacket water pump will cause a reduction in water pump efficiency. A reduction in water pump efficiency will result in low coolant flow.
If the cooling system is equipped with an aftercooler, check the aftercooler. A restriction of air flow through the air to air aftercooler can cause overheating of the engine. Check for debris or deposits which would prevent the free flow of air through the aftercooler.
The engine may be running excessively in the lug condition. When the load that is applied to the engine is too large, the engine will run in the lug condition. When the engine is running in the lug condition, engine rpm does not increase with an increase of fuel. This lower engine rpm causes a reduction in coolant flow through the system. The lug condition causes excess heat from the increase in fuel consumption.
Check for High Ambient Air Temperature
Determine if the ambient air temperature is within the design specifications for the cooling system. When ambient temperatures are too high for the rating of the cooling system, there is not enough of a temperature difference between the ambient air and coolant temperatures.
Determine the cause of the high air temperature. Correct the situation, when possible.
Check for High Inlet Air Restriction and/or High Altitude Operation
When inlet air pressure is low, the turbocharger works harder in order to achieve the desired inlet manifold pressure. This increases inlet air temperature.
Measure the inlet air pressure while the engine is operating under load. For specific data, refer to the Technical Marketing Information for the engine.
Check for plugged air filters. Check for obstructions to the air inlet. A restriction of the air that enters the engine can cause high cylinder temperatures. High cylinder temperatures cause higher than normal temperatures in the cooling system.
Replace the air filters and/or remove the obstruction from the air inlet.
Consider high altitude operation. The cooling capability of the cooling system is reduced at higher altitudes. A pressurized cooling system that has been designed for the higher altitudes must be used. Ensure that the engine is configured for high altitude operation.
Check for Exhaust System Restriction Check for a restriction in the exhaust system. A restriction of the air that is coming out of the engine can cause high cylinder temperatures.Expected Result:A problem has been found in the cooling system and/or the related engine systems.Results:
OK - A thorough inspection revealed a problem.Repair: Repair the problem. Ensure that the repair eliminates the problem.STOP