[This article was originally published in 2021 by Trucks, Parts, Service. It has been updated to include more timely information.]

Improper installation procedures are causing failures of new oil pumps when installers do not follow the correct steps for checking gear mesh and possible shim installation if needed, says AFA Industries. Oil Filter Housing

AFA Industries says the first step when installing a Cummins ISX oil pump is identifying which pump you may have.

Figure 1 shows the oil pump version with the pinned regulator plug that holds the oil pressure regulator in place in the pump. This pump must use shims upon installation.

Figure 2 shows the oil pump version with the thread-in regulator plug that holds the oil pressure regulator in place in the pump. This pump may or may not use shims upon installation.

Mechanical Seal Rings Follow steps in the tech tip for the correct procedure that will ensure the oil pump will properly perform in the engine.