Interstate-McBee M-3958645 Multi-Layer "Thick" Head Gasket – 2003–2007 5.9L Cummins ISB

Premium multi-layer steel (MLS) “thick” (Grade B) head gasket engineered to OEM form, fit, and function for 2003–2007 Dodge Ram 2500/3500 5.9L Cummins ISB (24-valve common-rail) engines. Ideal for rebuilds, resurfaced heads/blocks, or applications requiring the Grade-B thickness to maintain proper compression and piston-to-head clearance.

• OEM-style replacement: Interchanges with Cummins 3958645 (Grade B “thick”).
• MLS construction: Multi-layer stainless design with elastomer coating for durable sealing.
• Correct thickness grade: Grade-B (thick) selection for engines needing additional gasket height after machining.
• Fitment clarity: Built for 03–07 5.9L ISB common-rail; verify by engine serial number (ESN) for non-truck and QSB uses.
• Aftermarket value: Interstate-McBee quality at a lower cost than OEM boxed parts.

Specifications

Vehicle Fitment

Always confirm by ESN, especially for industrial/ag applications.

• Dodge Ram 2500/3500 5.9L Cummins ISB (24-Valve Common-Rail):
  • Model Years: 2003, 2004, 2005, 2006, 2007
• Industrial: Select QSB 5.9 applications may use 3958645 (verify by ESN).

Installation Notes

• Measure piston protrusion and surface finish; select Grade-B when required by spec.
• Follow Cummins service manual for head bolt torque sequence/angles and lubrication.
• Replace TTY head bolts or upgrade to studs; chase threads and check fastener stretch as applicable.
• Clean deck and head surfaces thoroughly; verify RA/Rz per OEM spec for MLS sealing.

What’s Included

• (1) Multi-Layer Steel head gasket, Grade B (thick)

Why Buy From CPP Diesel

• Diesel specialists with ESN-verified fitment support
• Fast shipping and easy returns
• Great bundle options with head bolts/studs, upper gasket sets, and coolant

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