ELBOW AS 2501498 - Caterpillar

Introduction
Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.Possible Paths for Debris
If repeat, low-hour (HEUI) pump failures occur, the following are possible paths of debris entering the system in operation. These paths are recommended areas for troubleshooting/inspection.Gasket (Oil Filter Base)
Illustration 1 g06035484
Oil filter base
Gasket may break away or receive damage, causing unfiltered oil to bypass filter. Check the gasket integrity and replace the gasket if damage is noted.Oil Cooler Flange
Illustration 2 g06035736
Concave cooler surface
Check oil cooler for flatness utilizing a straight edge or feeler gauge to inspect. Check locations where the gasket mates against the oil cooler flange, specifically between unfiltered and filtered oil cavities.Oil Filter Base (Check Valve Bypass)
Illustration 3 g06035832
Casting Porosity
Check bypass valve seat for porosity. The check valve is horizontal and directly above oil filter, facing forward.If porosity is present, replace the following:
Filter base
Spring
Valve
Oil cooler gasketSpring (Valve Bypass)
Inspect spring in oil filter check valve, ensure that spring is the most current design.Bypass Valve
Illustration 4 g06035874
Bypass valve
Inspect filter bypass valve, check to see that there are no leak paths.