Cummins 4089651 upper engine gasket kit, .020 thicker head gasket kit, 5.9L 12-valve Cummins 6BT, Dodge Ram 2500 3500 1989-1998, genuine Cummins B series gasket set, oversize head gasket rebuild kit, CPP Diesel Cummins OEM gaskets and seals.

Cummins 4089651 gasket set cross reference 4089649 3283339 3283335 4089650, Tier 1 5.9L B engine, upper engine gasket kit for decked block or cylinder head, OEM Cummins 6BT top end rebuild components.

CUMMINS 4089651 OEM UPPER ENGINE GASKET KIT (.020 THICKER HEAD GASKET) – 5.9L 12-VALVE (1989–1998)

When your 5.9L 12-valve Cummins has had the block or head surfaced, you need the correct oversize head gasket to get piston-to-head clearance and compression back where they belong. The Cummins 4089651 OEM Upper Engine Gasket Kit packages a +.020" thicker head gasket with the critical top-end seals you need to button up a proper rebuild on 1989–1998 Dodge Ram 2500/3500 5.9L 12V engines.

This is a genuine Cummins B-series 6BT upper gasket kit – no generic materials, no guesswork. You get OE-style multi-layer and composite gaskets designed to handle diesel cylinder pressures, thermal cycling, and long-haul duty so your freshened 12-valve stays sealed for the long run.

KEY FEATURES

• +.020" thicker OEM Cummins head gasket for resurfaced/decked blocks and cylinder heads.
• Complete upper engine gasket set for top-end service on 5.9L 12-valve Cummins (6BT).
• Genuine Cummins materials and profiles for factory-level sealing performance.
• Engineered primarily for Tier 1 5.9L B engines used in 1989–1998 Dodge Ram 2500/3500 and similar applications.
• One kit services one engine – ideal for head gasket jobs and upper-end overhauls.

FITMENT – VEHICLE & ENGINE

Engine: 5.9L Cummins 12-Valve (6BT) – Tier 1 B-series

Primary Automotive Applications:

• 1989–1993 Dodge D250 / D350 / W250 / W350 – 5.9L Cummins 12V
• 1994–1998 Dodge Ram 2500 – 5.9L Cummins 12V
• 1994–1998 Dodge Ram 3500 – 5.9L Cummins 12V

Important: Always confirm fitment by Engine Serial Number (ESN) before ordering. This kit is intended for 12-valve 5.9L engines where a +.020" oversize head gasket is required. For engines that have not been machined, use the standard-thickness kit or gasket listed in the cross-reference section below.

WHEN TO USE THE .020" THICKER GASKET

• Block deck and/or cylinder head has been machined and piston protrusion now requires a thicker gasket.
• You are following Cummins service information that specifies a +.020" head gasket based on measurement.
• You need to restore proper quench and compression after machine work on a 5.9L 12V Cummins.

WHAT'S INCLUDED (TYPICAL)

Kit contents may vary slightly by ESN, but typically include:

• +.020" oversize Cummins cylinder head gasket (6BT 5.9L 12V)
• Intake and exhaust manifold gaskets
• Valve cover and breather gaskets/seals
• Assorted upper engine seals and O-rings related to head service

For standard-thickness head gasket coverage with a complete upper kit, see Cummins 4089649 OEM Upper Engine Gasket Set – 5.9L 12-Valve (1989–1998).

CROSS-REFERENCE & RELATED CUMMINS PARTS

• Standard-thickness complete upper kit: Cummins 4089649 OEM Upper Engine Gasket Set – 5.9L 12-Valve (1989–1998)
• +.020" cylinder head gasket only: Cummins 3283339 OEM Cylinder Head Gasket (+.020) – 5.9L 12V (1989–1998)
• Standard-thickness cylinder head gasket: Cummins 3283335 OEM Cylinder Head Gasket – 5.9L 12-Valve (1989–1998)
• +.010" oversize upper engine gasket kit: Cummins 4089650 OEM Upper Engine Gasket Kit (.010 Oversize) – 5.9L 12-Valve (1989–1998)

Additional cross-reference numbers for this kit may include select Cummins and aftermarket references found in heavy-duty and industrial catalogs. Always verify by ESN and gasket thickness requirements before substituting.

INSTALL TIPS

• Measure piston protrusion and follow Cummins service information to confirm .020" oversize requirement.
• Ensure deck and head surfaces are clean, flat, and within Cummins surface finish specs.
• Use the correct torque sequence and fastener lube for head bolts or studs.
• Re-torque or angle-check fasteners only if specified by the service procedure.
• After first heat cycle, recheck coolant and oil levels and inspect for leaks.

FAQ

This Cummins 4089651 upper engine gasket kit is built for 5.9L 12-valve Cummins (6BT) engines commonly found in 1989–1998 Dodge Ram 2500/3500 trucks. You should still confirm by Engine Serial Number (ESN), especially on industrial or swapped applications, and make sure a +.020" head gasket is specified.

Use a dial indicator and straightedge to measure piston protrusion and compare to Cummins specifications. If machining has increased piston height relative to the deck, service information will call for a thicker gasket (like +.010" or +.020"). Only choose 4089651 when the measurements and Cummins charts confirm that +.020" is required.

Both are genuine Cummins upper engine gasket kits for 5.9L 12-valve engines. Part 4089651 includes a +.020" oversize head gasket for machined/decked engines. Part 4089649 includes a standard-thickness head gasket (3283335) for engines that have not been machined.

No. This is an upper engine gasket kit only. Head bolts or studs are sold separately. We strongly recommend new fasteners any time the head is removed, especially on high-mileage or performance builds.

This kit is a genuine Cummins OEM upper engine gasket kit, built to factory B-series 6BT specs. CPP Diesel sources Cummins-branded components so you can match OE sealing performance and durability.

Many diesel engine components fall under California Proposition 65 due to possible exposure to chemicals associated with engine operation and maintenance. For more information, visit www.P65Warnings.ca.gov.

SPECIFICATIONS FOR CUMMINS 4089651