Cummins 4928511 is the part number for the gasket on my ISC. It might be correct for the ISL, I have no knowledge. Cummins no longer sells separately as they want you to buy a new lift pump. You might find some old stock at a truck parts store. You might want to tighten slightly and see it the leak stops. That worked for me after replacing twice. Remember the lift pump is an AL alloy so do not overtighten. There are three bolts on top. I did find this note from Cummins:
Because of the fuel lift pump design differences, two service gaskets have been released. The Part Numbers are 4928511 and 4928512. These gaskets are not interchangeable. However, ISC/ISL CM554 engines built after approximately ESN 46319395 and ISX engines built after ESN 79055000 can use fuel lift pump gasket Part Number 4928512. To identify the correct gasket, inspect the face of the lift pump housing: โข Remove the three bolts on the top of the lift pump mounting adapter. โข Check for a support rib (see the new-style lift pump gasket illustration). Early-Style Lift Pump Gasket This lift pump housing takes gasket Part Number 4928511. New-Style Lift Pump Gasket This lift pump housing takes gasket Part Number 4928512. The gasket is located between the adapter and the lift pump housing. The correct gasket can also be determined by the lift pump serial number located on the side of the lift pump housing or on the lift pump mounting adapter. NOTE: The lift pump may need to be removed to read the serial number.
Dennis and Barb
2005 Safari Panther Diamond IV
1999 Monaco Windsor 40 SS (sold)
2002 Chevy Avalanche toad