SPIDER AS 8D1508 - Caterpillar

D399, G399 Engines Equipped With 2N2465 Prelubrication Oil Pump GroupThe 2N2465 Prelubrication Pump Group operates continuously to keep the oil passages full so the engine can be used in rapid start-up applications. Because of normal factory tolerances for the lubrication system, the amount of oil that gets to the upper parts of the engine can vary. In some applications too much oil gets to the turbocharger. The oil can then overflow into the intake manifold.
If an engine equipped with the prelubrication oil pump has a problem with too much oil in the system, a bypass valve can be installed. This bypass will control the amount of prelubrication oil that is sent directly to the sump. The result of this will be less flow of prelubrication oil in the system.
Install the parts for the bypass as shown in the illustration. The 4H5440 Cover is a part of the oil pan base group. Drill an 18.25 mm (.719") diameter hole in the center of the 4H5440 Cover. Cut 1/2"-14 NPTF threads in the cover.
To adjust the flow of prelubrication oil, first operate the engine until it is at normal operation temperature. Next, stop the engine and remove the pipe plug that is located in the center of the vee of the engine under the rear lifting eye. With the prelubrication pump in operation, oil will flow out of the hole on engines with too much flow of prelubrication oil. Adjust the valve until the oil just stops flowing out of the hole. Use wire or some other method to hold the valve in this position.
Installation of bypass components.