2004.5-2007 Dodge 5.9L Cummins Engine Components

Engine components on the 2004.5-2007 RAM 5.9L Cummins

This is an overhead-valve engine with four valves per cylinder and a solid-lifter camshaft. Pushrods drive the rocker arms, and valve bridges let each rocker open a pair of valves. Because the lifters are solid, valve lash is set by hand: 0.010 in on the intake and 0.020 in on the exhaust when resetting, with an allowable range of 0.006-0.015 in intake and 0.015-0.030 in exhaust. The check is due at 150,000 miles, and rocker bolts torque to 27 ft-lb. Down below, the stiffened common-rail block carries a front gear case located by dowel tubes in its lower bolts, so the killer dowel pin repair from older engines is not needed here.

What fails and why

The headline component failure on this engine is a cracked exhaust manifold. Repeated heat cycles crack the long casting, most often on trucks that tow. The signs are a tick or knock that gets louder with rpm, an exhaust smell, soot streaks around the manifold and lost power. Under the valve cover, the exhaust rockers must come off for every injector replacement, so rocker hardware comes off and goes back on any time injectors are replaced. On trucks with added fuel and the stock turbo, repeated high exhaust temperatures can drop a valve seat, which shows up as a sudden miss or knock and metal in the cylinder. Keep EGT under 1,500 F. Front and rear crankshaft seals and gasket sets are the parts you reach for when a high-mile engine is being resealed.

Stock replacement vs. upgrade

For a stock engine, Genuine Cummins and Mahle seals and gasket kits are the factory-style route: upper and lower gasket kits, timing gear case gaskets, crank seals with wear or repair sleeves, and a Cummins oil pump and camshaft gear. The upgrade side is about valvetrain and fasteners for trucks making more power. XDP lists heavy-duty rocker arm assemblies, billet valve bridges, rocker trunnion sets, high-boost and performance valve springs, street performance pushrods, bolt-on freeze plugs and an X220 head stud kit. Head studs make sense once boost goes past about 40 psi; factory bolts are fine at stock boost.

What we carry

Genuine Cummins parts include the 3937111 front crankshaft seal kit, the 4089819 upper and 4089173 lower engine gasket kits, the 5291050 oil pump, 5273413 camshaft gear, 4943979 connecting rod, 3949692 oil pickup tube and the 3957987 crankcase breather filter. Mahle adds the JV1690 rear main seal set, crankshaft and timing cover seals, the JV5076 gear case gasket, the CS54556 lower gasket set and the HS54556 head set. XDP covers valvetrain parts, a camshaft position sensor and bolt kits. Dorman has the dipstick and tube, expansion plugs and a clutch fan blade. You will also find an oil/fuel/coolant temperature sensor from Alliant Power, a replacement oil cooler from Mishimoto, and parts from Hamilton Cams, Fleece Performance Engineering, BD Diesel, Gator Fasteners and WCFab. For the rest of the truck, browse our Cummins parts.

Fitment notes

Several parts here are year-specific. The valve cover, breather and injector harness differ between 2003-2005 and 2006-2007 engines, and the Cummins 3957987 crankcase breather filter is listed for 2003-2005 only. The Cummins 3974981 rocker box housing is listed for 2006-2018. The Dorman 555-018 and 555-082 expansion plugs are listed through 2005, and the Dorman dipstick and tube through 2006. The Cummins 4943979 connecting rod is listed for 2004.5-2007. On 2007 trucks, confirm you have the 5.9L and not the 6.7L that took over partway through the model year. Verify by VIN before ordering.

Frequently asked questions

What is the valve lash spec on a 2004.5-2007 5.9L Cummins?

Set the intake at 0.010 in and the exhaust at 0.020 in when you reset. The allowable range is 0.006-0.015 in on the intake and 0.015-0.030 in on the exhaust. The check is due at 150,000 miles, and rocker bolts torque to 27 ft-lb.

Does the 2004.5-2007 5.9L need a killer dowel pin fix?

No. On 2003 and later engines the front gear case is located by dowel tubes in the lower bolts, so the dowel pin problem from 1989-2002 engines does not exist. The 1999-2001 53-block cracking issue does not apply to this engine either.

Why do the rockers come off when injectors are replaced?

On this engine the exhaust rockers must come off to replace an injector. When they go back on, torque the rocker bolts to 27 ft-lb. If the truck is near 150,000 miles, that is also the interval for a valve lash check, so it is a good time to do both.

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.