Product Description
Interstate-McBee MCB6BEXPKS — Expansion Plug Kit — 1989–2002 5.9L Cummins
Complete expansion (freeze/core) plug kit for the 5.9L Cummins B-Series engine family used from 1989–2002. Designed as an OE-equivalent solution to reseal the coolant passages during an engine rebuild or leak repair. Sold as a kit.
- Purpose-built kit: Includes the core plugs commonly replaced during block and cylinder head service.
- OE-style fit and finish: Matches factory dimensions for reliable sealing.
- Durable construction: Quality materials to withstand thermal cycling and corrosion.
Specifications
| Brand | Interstate-McBee |
| Part Number | MCB6BEXPKS |
| Engine | 5.9L Cummins B-Series (6BT/ISB) |
| Model Years | 1989–2002 |
| Sold As | Complete kit (expansion/core plugs) |
What’s Included
This kit contains the primary expansion/core plugs required for the engine block and head on 5.9L Cummins B-Series applications. Exact counts and diameters may vary by revision; compare to your engine before installation.
- Block expansion (freeze/core) plugs — assorted diameters
- Cylinder head expansion plugs (as applicable)
- Installation guidance notes (see below)
Vehicle Fitment
Always verify by engine serial number (ESN) for the most accurate fitment.
- Dodge Ram 2500/3500 — 5.9L Cummins
- 12-Valve 6BT: 1989–1998
- 24-Valve ISB: 1998.5–2002
- Other Cummins B-Series applications where this kit is specified (confirm by ESN).
Install Notes
- Clean bores thoroughly; remove corrosion and old sealant.
- Lightly coat plug edges with appropriate sealant if specified by your service manual.
- For cup-style plugs, set them squarely; drive until slightly below flush and evenly seated.
- Replace any damaged or pitted plugs rather than reusing.
- Refill with the correct coolant mixture and pressure-test after installation.
Recommended/Related Parts
- Block heater or replacement block heater plug (if equipped)
- Coolant/antifreeze and distilled water
- Thermostat and gasket (optional while servicing cooling system)
- Water pump (inspect/replace as needed)
Why Buy From CPP Diesel
- ESN-verified fitment support from diesel specialists
- Fast shipping, easy returns, competitive pricing
- Extensive inventory for Cummins B-Series service and rebuilds
FAQ
Will this kit fit both 12-valve and 24-valve 5.9L engines?
Yes. It covers the 5.9L Cummins B-Series used from 1989–2002. For edge cases, verify by ESN.
Do I need any special tools?
A suitable driver and sealant (as specified by your service manual) are recommended. A cooling-system pressure tester helps verify a leak-free install.
Can I reuse old plugs?
Reusing is not recommended. New plugs provide the best sealing and corrosion resistance.
