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Service bulletin WC-C-1638-B

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10058930
Published by NHTSA2015-12-23
Manufacturer's numberWC-C-1638-B
Manufacturer's date2015-06-12
NHTSA componentENGINE AND ENGINE COOLING:ENGINE:DIESEL

NHTSA's summary

CUMMINS: ON SOME ENGINES, A NEW BYPASS VALVE IS BASED ON CUMMINS MIDRANGE DESIGN THAT SEALING CAPABILITY IS MORE EFFECTIVE AND HAS BETTER PROTECTION FOR FUEL PUMP LUBRICATED COMPONENTS. MODEL ISX12, ISX15 CM2250, ISX12, ISX15 CM2350, QSX12, QSX15 CM2250ECF, CM2350, ISXE5. *PE

The document

No address for NHTSA's copy can be built for this communication. Ask the dealer for it by the manufacturer's number.

Components

Engine

Vehicles listed
CUMMINS CUMMINS

Listing a model year does not mean every vehicle of it is concerned: the document says which.