Product Description
Interstate-McBee M-3958645 Multi-Layer Thick Head Gasket — 2003–2007 5.9L Cummins (Aftermarket Replacement)
Premium multi-layer steel (MLS) head gasket for the 2003–2007 Dodge Ram 2500/3500 with the 5.9L Cummins 24-valve common-rail (ISB). This is the thick variant, designed for engines that require additional gasket thickness (e.g., after decking, higher piston protrusion, or specific build targets). Sold individually.
- MLS construction: Multiple embossed stainless layers with sealing coatings for durability and sealing integrity.
- Correct application: Matches Cummins reference 3958645 for 5.9L ISB common-rail engines (2003–2007).
- Thick spec: Helps maintain proper quench and compression after machine work; verify thickness by piston protrusion and build requirements.
- Interstate-McBee quality: Built to OE-style form, fit, and function.
Specifications
| Brand | Interstate-McBee |
| Part Number | M-3958645 |
| OEM Reference | Cummins 3958645 |
| Gasket Type | Multi-Layer Steel (MLS), Thick |
| Sold As | Each (1 head gasket) |
| Engine | 5.9L Cummins ISB, 24-valve Common-Rail |
What’s Included
- (1) MLS head gasket, thick specification
Vehicle Fitment
Always verify by engine serial number (ESN) and piston protrusion before ordering.
- Dodge Ram 2500/3500 5.9L Cummins (24-valve Common-Rail)
- Model Years: 2003, 2004, 2005, 2006, 2007
- Not for 1998.5–2002 24-valve VP44 or 1989–1998 12-valve engines.
- Not for 6.7L Cummins (2007.5+).
Install Notes
- Measure piston protrusion and select gasket thickness accordingly; follow Cummins service procedures.
- Ensure block deck and head surfaces are clean, flat, and within RA specs.
- Use new head bolts or upgrade to studs; follow the correct torque sequence and final values.
- Recheck coolant and oil after initial heat cycles.
Why Buy From CPP Diesel
- ESN-verified fitment support from diesel specialists
- Fast shipping, easy returns, competitive pricing
- Deep inventory of complementary gasket sets, bolts/studs, and top-end components
FAQ
Is this the correct gasket for my 2003–2007 5.9L Cummins?
Yes—this listing is for the 24-valve common-rail 5.9L (2003–2007). Verify by ESN and piston protrusion before finalizing thickness.
What does “thick” mean?
It’s a thicker-than-standard MLS gasket used to maintain proper quench and compression after machine work or when piston protrusion is on the higher side. Always measure to choose the correct thickness.
Do I need new bolts or studs?
Yes—head fasteners are torque-to-yield/critical hardware. Replace with new bolts or upgrade to studs and follow the specified torque sequence.
Does this fit 6.7L or earlier 12-valve/VP44 engines?
No—this part is specific to the 2003–2007 5.9L common-rail ISB.
