NUT 4L8341 - Caterpillar

The air induction and exhaust system consists of the air cleaner, air intake pipe, positive crankcase ventilator, inlet manifolds and exhaust manifolds.The inlet system is on top of the engine. The intake pipe provides for either a dry type or oil bath air cleaner. The pipe directs air to each cylinder head.The inlet manifolds are integrally cast as part of the cylinder heads. The manifolding, porting and combustion chamber design creates the air turblence necessary to assure complete combustion.The exhaust system manifolds mount along the outside of the cylinder banks and are not interchangeable.A positive crankcase ventilator mounts on top of a rocker arm cover. The positive crankcase ventilator valve vents crankcase fumes back into the engine through the intake pipe. The rocker arm cover on which the valve mounts is interchangeable between banks. However, the ventilator return pipe fitting must be interchanged with a plug in the intake pipe.The principal cause of fouled valves, damaged bearings, worn piston rings and cylinders is the entrance of airborne foreign matter into the engine cylinders. Therefore, it is necessary to incorporate a precision built air cleaner into the system. The intake ducts must be so arranged to be convenient to service, but located away from areas of dust and exhaust concentration. The importance of cleaning and/or filtering of the air entering the engine cannot be over-emphasized. Air tight connections are very important.Caterpillar recommends the use of an air cleaner service indicator for dry-type air cleaners. The service indicator senses pressure drop across the air cleaner and an indicator will remain visible when service is necessary. The service indicator will prevent unnecessary filter changes and reduce maintenance costs while ensuring proper engine operation.