Description

Cummins V-378 Parts Catalog

If you’ve ever ordered a part for a V-378 and got the wrong thing because you were working off a blurry aftermarket illustration, you know the frustration. That’s why I keep the original Cummins V-378 Parts Catalog on the bench. 37 pages of factory numbers, exploded views, and part callouts that match the engine in front of you. No guesswork.

Every group in this catalog is broken down by major assembly – from the Camshaft (page 6) to the air compressor (page 24). Each page shows the part, its number, and where it goes. If you’re rebuilding or chasing a oil leak, this is the difference between a one-shot order and three trips to the dealer.

Camshaft and Cover Assembly – Page 6

Camshaft wear isn’t something you guess on. Page 6 gives you the camshaft assembly including the cover, bolts, and thrust plate. Part numbers are listed with clear references. You’ll also find the camshaft bushings on page 4 – don’t order the cam without checking bushing wear. The catalog shows you which bushing goes where.

Page 4. Period. Always check bushing part numbers against your block serial number. The catalog makes that simple.

Cylinder Head and Gasket – Page 9

Head gasket failures on the V-378 are common when you run them hard. Page 9 shows the cylinder head assembly, head gasket, and all the associated hardware. You get the valve guide part numbers and the injector hold-down nuts. If you’re replacing a head, cross-check the gasket kit number on page 33 – it’s the same page as the gasket sets listing. One part number covers the whole job.

Fuel System Breakdown: Fuel Filter and Pump on Pages 28-29

Fuel system parts are easy to mis-order. This catalog dedicates pages 28 and 29 to the fuel filter, fuel pump, fuel pump drive, and fuel tubing. Each component is drawn with its own callout number. The gear pump is on page 27. If you’re chasing a fuel pressure drop, you can verify the exact filter head part number without pulling the old one first.

Cummins V-378 Parts Catalog: What’s Inside the 37 Pages?

Each page is an exploded diagram with a parts list. You get the cylinder block (page 1), crankshaft and main bearing shells (page 3), pistons and rings (page 4), front cover and gear housing (pages 5, 30), rocker levers (page 8), injectors (page 11), lubricating oil pump (page 12), oil pan and dipstick (page 13), oil filters (pages 14-15), oil cooler (page 16), fan hub (page 18), corrosion resistor (page 19), air intake manifold (page 22), air cleaner (page 23), air compressor (page 24-25), exhaust manifold (page 26), electrical equipment including alternator and starting motor (pages 31-32), flywheel and housing (page 33), plus radiator and instrument panel (page 32). Seventeen sections cover every wearable component.

Why Does OEM Documentation Matter?

Aftermarket parts catalogs re-draw the diagrams and sometimes transpose numbers. A friend of mine ordered a piston ring set from a third-party catalog and got rings that were 0.005” off. That’s a rebuild failure waiting to happen. This is a genuine Cummins document – same one the dealers use. You can verify any part against the engine serial number using the instructions on page 3. Write your model and serial number in the provided form. Then order from your local distributor. For more background on how these engines work, check this Wikipedia article on diesel engines or this Wikipedia article on diesel engines.

Related catalogs for other Cummins platforms include Cummins VME W380 Parts Catalog | 626-Page Factory Manual, Cummins QSX15-G8 2011 Parts Catalog – OEM Factory Manual, and Cummins 6BT5.9C Construction Parts Catalog 2004.

Does this catalog include torque specifications?

No. This is a parts catalog, not a service manual. It lists part numbers and assembly groups only.

How do I verify I’m ordering the correct part?

Use the engine model and serial number – the catalog has a form on page 3 for recording that data. Cross-reference the part number against the exploded view. If the part has a casting number on it, match that to the catalog number. When in doubt, call your Cummins distributor with the serial number and the page reference. That extra step prevents returns. The catalog emphasizes “always specify engine model and serial number” – it’s printed right on page 3. Ignore that and you risk getting a piston that doesn’t fit the liner bore. The cylinder liner itself is on page 1, and the piston and rings on page 4 – they must match by part number group. One mis-matched ring set can score a cylinder wall inside 50 hours of run time. Take the two minutes to verify.

Access the Factory Manual – this is the exact PDF you need for accurate parts ordering on a Cummins V-378. No aftermarket reprints, just the original factory file with all 37 pages intact.