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CUMMINS

CUMMINS 3978517 OEM CYLINDER HEAD GASKET (.020 MARINE) – RAM 5.9L ISB (2003–2007)

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SKU:
CUM3978517
MPN:
3978517
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  • CUMMINS 3978517 OEM CYLINDER HEAD GASKET (.020 MARINE) – RAM 5.9L ISB (2003–2007)
  • CUMMINS 3978517 OEM CYLINDER HEAD GASKET (.020 MARINE) – RAM 5.9L ISB (2003–2007)
  • CUMMINS 3978517 OEM CYLINDER HEAD GASKET (.020 MARINE) – RAM 5.9L ISB (2003–2007)
$512.79
724-785-4022

Description

Genuine Cummins

Cummins 3978517 — Cylinder Head Gasket (.020 Marine Thickness)

MPN: 3978517  |  Also Known As: head gasket, MLS gasket  |  Applications: 2003–2007 Ram 5.9L ISB & QSB5.9 (CPL 1860/8732)

Why This Part

  • ✓ OE multi-layer steel (MLS) gasket for reliable combustion sealing.
  • ✓ +.020" marine thickness helps compensate for deck/head machining and supports high-boost builds.
  • ✓ Direct-fit for 2003–2007 Ram 5.9L ISB; widely used on QSB5.9 marine/industrial.
  • ✓ Durable fire-ring design resists blow-by and fluid cross-leaks.
OE Fit +.020 Thickness 1 Per Engine

Quick Specs

Type Cylinder Head Gasket (MLS)
OE Part # 3978517
Thickness +.020" marine
Qty Required 1 per engine (sold individually)

Verified Fitment (Automotive)

Year RangeEngineChassis
2003–2007 Ram 5.9L ISB (24V Common-Rail) Ram 2500/3500

Industrial/Marine: QSB5.9 (incl. CPL 1860 & 8732). Always confirm by ESN/CPL to ensure the correct thickness.

Often Paired With

  • Head Bolts: Cummins 3927063 (set of 26) or ARP 247-4202 head studs
  • Upper gasket items: intake/exhaust manifold gaskets, valve cover seals
  • Fresh coolant & oil after head service

What’s In The Box

  • (1) Genuine Cummins Cylinder Head Gasket (.020) — 3978517
  • Fasteners & additional gaskets sold separately (see “Often Paired With”).

Install Tips

  • Verify gasket thickness based on piston protrusion and any machining.
  • Check deck/head flatness and surface finish; clean oil & coolant passages.
  • Use new bolts/studs and torque in proper sequence and stages per Cummins spec.

FAQ

WILL THIS FIT MY 2003–2007 5.9L CUMMINS RAM?

Yes—3978517 is widely used on 2003–2007 5.9L ISB (common-rail) and QSB5.9 platforms. Confirm thickness by ESN/CPL and piston protrusion.

IS THIS THE +.020" MARINE-THICKNESS GASKET?

Yes—this listing is the +.020" marine thickness version, favored when the head/block has been machined or for high-boost builds.

HOW DO I PICK THE RIGHT THICKNESS?

Measure piston protrusion and account for any deck/head machining. Choose thickness to maintain proper quench and compression.

DO I NEED NEW HEAD BOLTS OR STUDS?

Yes—new OE bolts (3927063) or ARP studs are recommended for consistent clamping and long-term sealing.

IS THIS A GENUINE CUMMINS PART?

Yes—OE Cummins 3978517 with MLS construction and factory-specified sealing layers.

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Additional Information

Vehicle Year:
2003,2004,2005,2006,2007
Vehicle Make:
DODGE
ENGINE:
5.9L
Part Type:
Marine Head Gasket
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