Product Description
Cummins 4938189 — Expansion Plug (Freeze/Core Plug), ~2.300" OD
MPN: 4938189 | Also Known As: freeze plug, core plug, cup-style expansion plug | Size: ~2.300" outside diameter
Why This Part
- ✓ OE cup-style plug to properly seal the block’s core holes.
- ✓ Direct-fit for common B-Series automotive applications (see fitment).
- ✓ Leak prevention to protect cooling system performance.
- ✓ Built to Cummins specifications for durability and correct interference fit.
Quick Specs
| Type | Expansion plug (freeze/core plug), cup-style |
|---|---|
| OE Part # | 4938189 |
| Outside Diameter | ~2.300" |
| Qty Required | Varies by engine/block; sold individually |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 2003–2007 | Ram 5.9L ISB (24V Common-Rail) | Ram 2500/3500 |
| 2007.5–2018 | Ram 6.7L ISB (24V Common-Rail) | Ram 2500/3500 |
Industrial/Off-Highway: Used across B-Series platforms (e.g., B3.9, B4.5, B5.9, B6.7 / ISB/QSB). Cummins notes primary use on certain BS3 5.9L B engines; always verify by ESN and block casting before ordering.
Often Paired With
- Coolant: refill/bleed after plug replacement.
- Complementary plugs: replace additional side/rear plugs while you’re in there.
- Block heater (as applicable) and new sealing grommet.
What’s In The Box
- (1) Genuine Cummins Expansion Plug (4938189)
Install Tips
- Clean the bore thoroughly; remove corrosion and old sealant.
- Align square and drive in evenly to the specified depth; do not distort the cup.
- Use sealant only if the Cummins service procedure for your block calls for it; pressure test after refill.
FAQ
WILL THIS FIT MY 2003–2018 RAM 5.9L/6.7L?Yes—this cup-style expansion plug is used on many B-Series automotive blocks (’03–’07 5.9L and ’07.5–’18 6.7L). Always verify by VIN/ESN and measure the bore to confirm ~2.300" OD.
WHAT’S THE OUTSIDE DIAMETER?Approximately 2.300" OD (measure the block bore to confirm before pressing in).
HOW MANY DO I NEED?Sold individually. The engine block uses multiple core plugs; quantity depends on which locations you are servicing.
DO I NEED SEALANT?Follow the Cummins service manual for your specific block casting. Some procedures specify dry install; others call for a thin sealant film.
IS THIS A GENUINE CUMMINS PART?Yes—OE Cummins 4938189 for proper interference fit and durability.
