94900-20420 SCREW, COUNTERSUNK Denso Cross

Operation of ATAAC
Heated compressed air from the engine turbocharger is conveyed to an air-to-air aftercooler that is positioned in front of the engine radiator. The combined effect of the engine fan and ram air moves cooled air through the system to reduce the turbocharged air temperature before it enters the engine intake manifold.Lower intake air temperature allows more air to enter the cylinder, resulting in more complete fuel combustion and reduced exhaust emissions.Air-to-air aftercoolers can achieve charge air temperatures lower than water-to-air systems for additional efficiency.
To maintain an adequate water pump cavitation temperature for efficient water pump performance in an Air-to-Air aftercooled engine, Caterpillar recommends that the coolant mix contain a minimum of 30% Caterpillar Antifreeze, GM-6038M or equivalent.Only use a greater concentration (above 30%) of antifreeze as needed for anticipated outside temperatures.Ethylene glycol raises the boiling point of water.Do not exceed a coolant mixture of 60% ethylene glycol to water since a concentration above 60% ethylene glycol will reduce the engine's freeze protection and increase the possibility of deposit formation in the cooling system.Dowtherm 209 Full-Fill coolant cannot be substituted for ethylene glycol, due to its inability to raise the water pump cavitation temperature. Dowtherm 209 Full-Fill coolant lowers the boiling point of water.
Air Intake System
Never run the engine without an air cleaner installed or with a damaged air cleaner. Dirt will enter the engine and cause premature wear and damage to engine components.Service the air cleaner at regular intervals as determined by the operating environmental dust conditions. Check the air cleaner service indicator (if equipped) daily.As the air cleaner element becomes plugged, the difference of air pressure between the inlet side (dirty side) and the engine side (clean side) will increase. Service the air cleaners regularly or when the air cleaner service indicator diaphragm enters the red zone or the red piston locks in the visible position.Inspect the air intake hoses, elbows and gaskets for cracks or damage, replace as needed. Check for loose clamps, tighten as needed.Check the precleaner (if equipped) daily for accumulation of dust and debris.The Caterpillar air cleaner element may be cleaned up to six times, but must be replaced annually. The element when cleaned, should be thoroughly checked for rips and tears in the filter material and for gasket damage.Winter Fronts
Caterpillar discourages the use of winter fronts or other air flow restriction devices mounted in front of radiators with air-to-air aftercooled engines. Air flow restriction can cause higher exhaust temperatures, power loss, excessive fan usage, a reduction in fuel economy and possible engine damage.If a winter front must be used, then it should have a permanent circular or diamond-shaped opening directly in line with the fan hub and must have a minimum opening dimension of at least 120 sq. in. (770 sq. cm).A centered opening, versus a side or edge winter front opening is specified to provide sensing when viscous fan drives are used and/or to prevent an interrupted air flow on the fan blades that could cause a fan failure.The