Cummins 3929881 — Genuine Exhaust Manifold Gasket (MLS) for 5.9L 12-Valve

MPN: 3929881  |  Also Known As: exhaust manifold-to-head gasket, MLS manifold gasket

Genuine Cummins multi-layer steel (MLS) gasket that seals the exhaust manifold to the cylinder head on 1989–1998 5.9L 12-valve (6BT) applications. Built to handle heat cycling and higher EGTs common in towing and performance use. Sold individually; typically 6 required per engine on 12-valve trucks.

Features & Benefits

• MLS construction resists blowouts and maintains clamp load under extreme heat.
• OE fit for quick installation with stock manifolds or quality replacements.
• Restores seal to reduce exhaust leaks, soot, and tick noises at the head flange.
• Durable coating for corrosion resistance and easier removal later.

Verified Fitment (Automotive)

Industrial/Off-Highway: Broad use across B-Series families (4B/6B, ISB, QSB). Verify by ESN for non-automotive engines.

Specifications

• Type: Exhaust manifold to cylinder head gasket (MLS)
• OE Part Number: 3929881
• Material: Multi-layer stainless steel with heat-resistant coating
• Quantity Required: Sold individually; typically 6 per engine on 12V applications

Often Paired With

• Turbo-to-manifold gasket: Cummins 3901356
• Exhaust manifold hardware: bolts/spacers (e.g., Cummins 3945252 spacer) and studs/nuts as needed

What’s In The Box

• (1) Genuine Cummins Exhaust Manifold Gasket (3929881)

Installation Tips

• Remove rust/soot from mating surfaces; check manifold for warpage or cracks.
• Use correct torque sequence and re-torque after heat cycle if required by the manifold maker.
• When manifolds are off, inspect turbo studs and replace gaskets/hardware as needed.

FAQ

WILL THIS FIT MY 1989–1998 5.9L 12-VALVE CUMMINS?

Yes—3929881 is an OE manifold-to-head gasket for 5.9L 12V (6BT) Ram 2500/3500. Industrial 4B/6B/ISB/QSB engines may also use it—verify by ESN.

HOW MANY GASKETS DO I NEED?

Most 12V applications use six manifold-to-head gaskets (sold individually). Some kits bundle sets; count your ports and order accordingly.

DOES THIS FIT 24V (1998.5–2002) OR COMMON-RAIL ENGINES?

No—24V and CR engines use different gasket part numbers/sets. Choose a 24V-specific or 1998.5–2018 set instead.

IS THIS AN MLS GASKET?

Yes—3929881 is a multi-layer steel (MLS) design for better heat cycle durability and sealing performance.

IS THIS GENUINE CUMMINS?

Yes—OE Cummins part 3929881 for proper fit and durability.