Product Description
Genuine Cummins
Cummins 3954829 — Thermostat Housing Seal (O-Ring)
MPN: 3954829 | Also Known As: thermostat seal, thermostat O-ring, housing seal | Cross-Ref (ID only): Interstate McBee M-3954829
Why This Part
- ✓ OE sealing between the thermostat and housing to prevent coolant leaks.
- ✓ Direct-fit for Ram 5.9L/6.7L ISB (see fitment below).
- ✓ Heat- and coolant-resistant elastomer for long service life.
- ✓ Low-cost insurance whenever servicing the thermostat or housing.
OE Fit Stock Replacement 1 Per Thermostat
Quick Specs
| Type | Thermostat housing seal (O-ring) |
|---|---|
| OE Part # | 3954829 |
| Location | Seals thermostat to housing / housing to engine |
| Qty Required | 1 per service (sold individually) |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 2003–2018 | Ram 5.9L / 6.7L ISB (24V Common-Rail) | Ram 2500/3500 |
Notes: Widely used across ISB/QSB 5.9/6.7 platforms. Some sellers list coverage beyond these years; always verify by VIN/ESN due to running changes.
Often Paired With
- Thermostat (OE temperature) during cooling system service
- Thermostat Housing or hardware if damaged/corroded
- Coolant (fresh fill) after sealing work
What’s In The Box
- (1) Genuine Cummins Thermostat Housing Seal (3954829)
Install Tips
- Clean mating surfaces thoroughly; do not use sealants unless specified by OEM.
- Lightly lubricate the O-ring with coolant before installation.
- Torque housing fasteners to spec and refill/bleed the cooling system.
FAQ
WILL THIS FIT MY 5.9L OR 6.7L CUMMINS RAM?Yes—this OE seal is commonly used on 2003–2018 Ram 5.9L/6.7L ISB applications (verify by VIN/ESN).
IS THIS AN O-RING OR A FLAT GASKET?It’s an O-ring style seal that sits between the thermostat and housing.
SHOULD I REPLACE THIS WHEN DOING A THERMOSTAT?Yes—replacing the seal anytime the housing is opened helps prevent leaks and comebacks.
IS THIS A GENUINE CUMMINS PART?Yes—OE Cummins 3954829 for proper fit and durability.
WHAT’S THE AFTERMARKET CROSS-REFERENCE?Interstate McBee M-3954829 is a common aftermarket cross-reference (for identification only).
Product Videos
Custom Field
Vehicle Year 2003,2004,2005,2006,2007,2008,2009,2010,2011,2012
Vehicle Make DODGE
ENGINE 5.9L,6.7L
Part Type Thermostat Housing Seal
