GUARD AS 3847392 - Caterpillar

Probable Causes
Engine lugging
Air inlet restriction or air inlet leak
Exhaust restriction or exhaust leak
Incorrect fuel timing dimension
Incorrect fuel settingRecommended Repairs
Engine Lugging
An engine that is operated at lower engine speeds may lug. The low rpm causes a reduction in air flow through the radiator. The low rpm also causes a reduction in the flow of coolant through the system. The combination of less air flow and less coolant flow during high input of fuel will cause above normal heating.Air Inlet Restriction or Air Inlet Leak
An air inlet restriction can cause cylinder temperature to increase. This will transfer more heat to the exhaust system. Check the air flow with a water manometer or a vacuum gauge. Connect the gauge to the engine air inlet between the air cleaner and the inlet to the turbocharger. Check the air flow with the engine at full load rpm. The maximum allowable air inlet restriction is 6.25 kPa (25 inches of H2O). If the indication is higher than the maximum permissible restriction, clean the filter element or install a new filter element. Check the restriction again. If the restriction remains too high, inspect the air inlet piping for obstructions. Check pressure in the air inlet manifold. Check for air inlet leaks. Look for restrictions at the air cleaner. Check for leaks between the exhaust manifold and the turbocharger. Correct any leaks.Exhaust Restriction or Exhaust Leak
An exhaust restriction can cause cylinder temperature to increase. This will transfer more heat to the exhaust system. Make a visual inspection of the exhaust system. Check for damage to piping or for a faulty muffler. If no damage is found, check the exhaust system for back pressure from the exhaust (pressure difference measurement between exhaust outlet and atmosphere). Refer to Systems Operation, Testing And Adjusting, "Restriction Of Air Inlet And Exhaust". Check the system by removing the exhaust pipes from the exhaust manifolds. Operate the engine without the exhaust pipes. If the problem is corrected, the exhaust pipes have an obstruction. If there is a leak in the exhaust system, find the cause of the exhaust leak. Make any necessary repairs.Incorrect Fuel Timing Dimension
Check and make necessary adjustments. Refer to the Systems Operation, Testing And Adjusting module.Incorrect Fuel Setting
A high fuel setting causes a high heat rejection. Check the fuel setting and make necessary adjustments. Refer to the Systems Operation, Testing And Adjusting module. Also refer to TMI (Technical Marketing Information), "Fuel Setting And Related Information".