Cummins 4089650 Upper Engine Gasket Kit .010 Over - 1989-1998 5.9L 12V Cummins

The Cummins 4089650 upper engine gasket kit is the OE-sourced top-end sealing package for the 1989-1998 Dodge 5.9L 12 Valve Cummins, built identically to the standard 4089649 kit but with a .010" over-thickness head gasket for applications where machining, resurfacing, or rebuild specifications call for added gasket thickness. All other upper-engine sealing components - exhaust manifold gaskets, valve cover gasket, intake gasket, injector seals, turbocharger gasket, and all associated seals - are included. This is the 10-over variant. Two other thickness options exist for this same application. For a complete engine reseal, pair with the OE Cummins lower engine gasket kit to cover the bottom-end sealing path.

Which Thickness Variant Is Correct?

Three upper engine gasket kit variants exist for the 1989-1998 5.9L 12 Valve Cummins, differing only in head gasket thickness. The 4089650 uses a .010" over-thickness head gasket, helping restore proper deck clearance and sealing geometry when your rebuild specification calls for added thickness. If your machine shop spec calls for 10 over, this is the correct kit to order. If you are unsure which thickness your application requires, confirm with your machine shop before ordering.

The Valve Seal Decision - Read Before Building

This kit includes new-style top hat valve stem seals (Cummins 3957912 - 12 seals). Installing these requires machining. Most builders set the included top hat seals aside and use the old-style press-on seals instead. If your machine shop is not performing valve seal seat machining as part of this job, order the old-style press-on seals (Cummins 3921640) separately. If your machine shop is performing the seat machining as part of the rebuild, the included top hat seals are the correct upgrade path. Confirm your valve seal plan before starting the job.

What Comes in the 4089650 Kit

The 4089650 contains the same components as the standard 4089649 kit with one difference: the head gasket is .010" over-thickness. All other Cummins component numbers are identical to the standard kit.

• .010" over-thickness head gasket - Cummins 3283335 D specification (OEM Gasket, Cylinder Head) x1
• Exhaust manifold gaskets - Cummins 3929881 x6
• Valve cover gasket - Cummins 3930906 x6 (includes noise isolators 3935449 x6)
• Intake manifold cover gasket - Cummins 3938152 x1
• Turbocharger gasket - Cummins 3901356 x1 (Holset P/N: 3709861)
• Exhaust outlet connection gasket - Cummins 3912220 x1
• Thermostat housing cover gasket - Cummins 3923331 x1
• Injector seals - Cummins 3900808 x6, 3923261 x6, 3930324 x6, 3937142 x6
• Injector sleeves - Cummins 3919358 x6
• Banjo connector seals - Cummins 4942278 x6
• O-rings - Cummins 3883284 x1, 3910824 x6
• Rectangular ring seals - Cummins 3906694 x1, 3936876 x1
• Sealing washers - Cummins 3902425 x1, 3906773 x1, 3918188 x2, 3963988 x2
• Oil drain gasket - Cummins 3937706 x1
• Valve stem seals (top hat style, machine work required) - Cummins 3957912 x12

The valve stem seals included are top hat style and require machine work to install on most engines. If your rebuild does not include valve seat machining, order the old-style press-on seals 3921640 separately and use those instead.

Cummins 4089650 Specs

Confirm your head gasket thickness requirement and model year - then this is the correct kit to order.

If your year, engine, and .010" over thickness spec all match, the Cummins 4089650 is the correct upper engine gasket kit to order.

Avoid These Common Mistakes

• Wrong thickness variant: Three kits exist - standard (4089649), .010" over (4089650), and .020" over (4089651). Confirm your rebuild spec with your machine shop before ordering.
• Installing the included top hat seals without machine work: The Cummins 3957912 top hat seals require machining to install. Without that machine work, use the old-style press-on seals (3921640) instead.
• Assuming this is a complete reseal kit: The 4089650 covers upper-engine components only. Add the OE Cummins lower gasket kit for a full engine reseal.
• Wrong engine generation: This kit is 12 Valve only - does not fit 1998.5 and newer 24 Valve Cummins trucks.

1989-1998 12 Valve Cummins Fitment

Fits all 1989-1998 Dodge applications with the 5.9L 12 Valve Cummins engine.

• 1994-1998 Dodge Ram 2500 5.9L 12 Valve Cummins
• 1994-1998 Dodge Ram 3500 5.9L 12 Valve Cummins
• 1989-1993 Dodge D250 5.9L 12 Valve Cummins
• 1989-1993 Dodge D350 5.9L 12 Valve Cummins
• 1989-1993 Dodge W250 5.9L 12 Valve Cummins
• 1989-1993 Dodge W350 5.9L 12 Valve Cummins

Does not fit 1998.5 or newer 24 Valve Cummins applications.

Final Checks Before You Order

• Engine confirmed as 5.9L 12 Valve Cummins
• Model year confirmed within 1989-1998 range
• Rebuild spec confirmed for .010" over-thickness head gasket
• Valve seal plan confirmed - top hat seals (3957912) require machine work; old-style press-on seals (3921640) ordered separately if needed
• Lower gasket kit added to order if a complete engine reseal is planned

For a 1989-1998 5.9L 12 Valve Cummins top-end rebuild where machining or resurfacing calls for .010" added gasket thickness, the Cummins 4089650 is the correct upper engine gasket kit to order.

Frequently Asked Questions