CUMMINS 3929881 OEM EXHAUST MANIFOLD GASKET (MLS) – 6BT 5.9L 12-VALVE (1989–1998)

Product Description

The CUMMINS 3929881 OEM EXHAUST MANIFOLD GASKET is the factory multi-layer steel (MLS) gasket that seals the exhaust manifold to the cylinder head on 6BT 5.9L 12-valve Cummins engines. If you are chasing hot-side leaks, slow spool, or soot tracks around the manifold, this genuine Cummins gasket restores the OE seal you expect on your 1989–1998 Dodge Ram workhorse and B-series applications. CUMMINS 3929881 exhaust manifold gasket, genuine Cummins MLS manifold gasket, 6BT 5.9L 12V exhaust gasket, 1989-1998 Dodge Ram 2500 3500 5.9 Cummins manifold gasket, OEM Cummins B series gasket, stock replacement exhaust gasket, CPP Diesel Cummins genuine parts

Built as a true multi-layer stainless steel (MLS) gasket, 3929881 handles extreme exhaust gas temperatures, thermal cycling, and manifold movement without crushing or blowing out like cheap composites. Whether you are keeping a bone-stock farm truck sealed up or supporting a tuned 12-valve running elevated EGTs, this Cummins-branded gasket gives you the same seal the engine left the factory with.

Fitment – CUMMINS 3929881 Exhaust Manifold Gasket

• Engine: Cummins 6BT / B5.9, 12-valve, inline-6 diesel
• Displacement: 5.9L
• Vehicle: Dodge / Ram 2500 & 3500 trucks equipped with 5.9L 12V Cummins
• Model years (on-highway): Approx. 1989–1998 5.9L 12-valve applications (verify by ESN for industrial/medium-duty)
• Location: Exhaust manifold to cylinder head gasket (one per port)
• Quantity required: Typically six (6) gaskets per engine on 12-valve applications

Key Features

• Genuine Cummins part number 3929881 – direct from the OEM, not a generic copy.
• Multi-layer steel construction (MLS) – resists blowouts and maintains clamp load under high heat.
• Precise B-series port geometry – matches factory 6BT 5.9L 12V exhaust ports for clean flow.
• Leak-free sealing – helps restore turbo spool, low-end torque, and keeps under-hood soot in check.
• Service-friendly – drop-in replacement whenever manifolds are swapped, resurfaced, or upgraded.

Cross-Reference & Related Cummins OEM Parts

Keep your hot-side sealed up by pairing this gasket with other genuine Cummins exhaust and turbo gaskets available from CPP Diesel:

• CUMMINS 3927154 OEM EXHAUST MANIFOLD GASKET – 5.9L CUMMINS (1989–1998)
• CUMMINS 3949530 OEM T3 TURBOCHARGER TO EXHAUST MANIFOLD GASKET – 5.9L ISB (2003–2007)
• CUMMINS 5260648 OEM TURBO TO MANIFOLD GASKET (T4i) – 6.7L ISB (2007.5–2012)
• CUMMINS 5339363 OEM TURBOCHARGER FLANGE GASKET – ISB 6.7L (2019–2024)

What’s Included

• (1) Genuine Cummins exhaust manifold gasket – part number 3929881

Note: Order six (6) gaskets per engine for typical 6BT 5.9L 12-valve on-highway applications.

Installation Notes

• Always work on a cool engine; remove the manifold and old gaskets carefully to avoid scoring the head.
• Clean mating surfaces thoroughly to bare metal – remove rust, carbon, and old gasket material.
• Inspect the exhaust manifold for warpage or cracks; repair or replace as needed before install.
• Install gaskets dry unless explicitly directed otherwise by the Cummins service manual.
• Torque manifold hardware in the factory sequence and to the correct specification.
• After a few heat cycles, recheck torque if your service procedure calls for it.

FAQ – CUMMINS 3929881 Exhaust Manifold Gasket

How many CUMMINS 3929881 gaskets do I need for a 5.9L 12-valve?

The 6BT 5.9L 12-valve uses one gasket per exhaust port. A complete manifold service on a six-cylinder engine typically requires six (6) gaskets. Always verify your specific engine build and parts diagram before ordering.

Will this fit my 24-valve 5.9L or 6.7L Cummins?

No. Part number 3929881 is targeted at 12-valve B-series/6BT applications, including 1989–1998 Dodge/Ram 2500/3500 trucks. Later 24-valve 5.9L and 6.7L engines use different exhaust manifold gaskets and hardware. For those engines, use the correct Cummins gasket part numbers listed on CPP Diesel.

Is this gasket suitable for performance or tuned 12-valve builds?

Yes. Because this is an OEM multi-layer steel gasket, it is commonly used on both stock and mildly to aggressively tuned 12-valve setups. As long as your exhaust manifold is flat, hardware is in good shape, and torque procedures are followed, this gasket can handle elevated EGTs typical of towing and street performance builds.

Do I need any sealant on the MLS gasket?

In most cases, no additional sealant is required on a multi-layer steel gasket like 3929881. Install it clean and dry on properly prepared surfaces unless a Cummins service document for your specific application calls for a different procedure.

Can I reuse CUMMINS 3929881 gaskets after removing the manifold?

Reusing exhaust manifold gaskets is not recommended. Once they have been compressed and heat-cycled, they may not seal correctly a second time. For best results and to avoid repeat labor, replace the gaskets anytime the manifold is removed.

Specifications for cummins 3929881