2004.5-2007 Dodge 5.9L Cummins Exhaust Manifolds

The exhaust manifold on the 2004.5-2007 RAM 5.9L Cummins

The 5.9L Cummins uses a one-piece cast-iron log manifold that collects all six cylinders and feeds the Holset HE351CW turbo. It's a long casting on a long inline-six, and that length is the problem. Every heat cycle makes it grow and shrink, and over the years that cycling cracks it. For other trucks, see our main exhaust page.

What fails and why

Two things go wrong. First, the manifold cracks. You'll hear a loud ticking or knocking that grows with rpm, notice a drop in power, and find soot at the crack. It's very common with age. Second, once the manifold warps, the manifold-to-head bolts and the turbo flange become leak points, with exhaust leak noise, smell and soot streaks at the head.

Stock replacement vs. upgrade

For a cracked casting, the standard fix is a replacement manifold with new hardware installed at the same time. If you're replacing the manifold anyway, the ATS Diesel Performance Pulse Flow kit, listed for 2003-2007 5.9L, is the aftermarket option in this section. Leaks at the head bolts and turbo flange show up once the manifold warps, so check the casting before you order only gaskets. Hardware choice is mostly preference: studs with nuts, or bolts with spacers, in black oxide, chrome or stainless.

What we carry

• Manifold: ATS Diesel Performance Pulse Flow exhaust manifold kit (2003-2007 5.9L).
• Gaskets: MAHLE MS19225 gasket set, the ATS 204-004-2218 manifold-to-head gasket, and the BD Diesel 1045986 gasket set and kits.
• Stud kits: Gator Fasteners EMSK5967C heavy-duty kits in black oxide or chrome, Fleece Performance Engineering kits with a 7mm external hex head or a 4mm Allen socket head, the PPE 216110200 and the Mishimoto MMEXH-RAM-94SK.
• Bolt kits: Dorman 03417B bolts, the XDP XD230 stainless bolt kit, and the PPE 216110100 and BD 1045982 bolt-and-spacer kits.
• Adapters: the BD 1044106 T3-T4 manifold adapter flange and the ATS 213-045-1000 45mm wastegate adapter, for owners changing turbo or wastegate setups.

Fitment notes

Most of the hardware here is listed with wide ranges that cover both the 5.9L and 6.7L Cummins, such as 1994-2018 or 1998.5-2018. The ATS manifold and the ATS manifold-to-head gasket are listed for the 5.9L only. BD's gasket kit comes in more than one version, so read the product page before ordering. On a 2007, confirm the engine, because 5.9L and 6.7L trucks share that model year. Verify by VIN.

Frequently asked questions

What does a cracked exhaust manifold sound like?

A loud ticking or knocking from the manifold area that grows as rpm rises. You may also notice a loss of power and find soot at the crack. On this engine it's very common with age.

Should I replace the bolts when I replace the manifold?

Yes. The standard repair is a replacement manifold with new hardware installed at the same time. The bolts are a known leak point once a manifold warps, which is why this section carries bolt kits from Dorman, XDP, PPE and BD, plus stud kits if you'd rather go that route.

Studs or bolts: which kit should I buy?

Both are listed for this engine. Stud kits come from Gator Fasteners (black oxide or chrome), Fleece (7mm hex or 4mm Allen head), PPE and Mishimoto. Bolt kits come from Dorman, XDP (stainless), and PPE and BD with spacers. Pick by head style and finish, and check the product page for the year range.

Not sure what fits? Call the shop at the number in the header, or use the fitment checker on any product page. We install everything we sell.