Product Description
Interstate-McBee M-3954829 Thermostat Housing Seal – 2003–2018 5.9L / 6.7L Cummins
Direct-replacement thermostat housing seal that restores a proper coolant-tight joint between the thermostat housing and the engine. Built to OE form, fit, and function. Sold individually.
- OE-style fit: Matches Cummins reference 3954829 for applications that specify this seal.
- Reliable sealing: Quality materials resist heat, coolant additives, and long service intervals.
- Service friendly: Ideal for thermostat or housing service; replace the seal anytime the housing is opened.
- Value: Interstate-McBee quality at an aftermarket price.
Specifications
| Brand | Interstate-McBee |
| Part Number | M-3954829 |
| OEM Reference | Cummins 3954829 |
| Location | Thermostat housing to engine |
| Sold As | Each (1 seal) |
What’s Included
- (1) Thermostat housing seal, P/N M-3954829
Vehicle Fitment
Always verify by engine serial number (ESN) or OEM part number.
- Ram 2500/3500/4500/5500 with Cummins B-Series where Cummins 3954829 is specified:
- 5.9L (ISB/6BT): 2003–2007
- 6.7L (ISB): 2007.5–2018
- Other B-Series applications that call for Cummins 3954829 (confirm by ESN).
Recommended/Related Parts
- Thermostat (choose correct temperature for your application)
- Thermostat housing (if pitted or corroded)
- Coolant and distilled water for refill/bleed
- New fasteners if originals are corroded
Install Notes
- Clean mating surfaces thoroughly; remove old gasket material and corrosion.
- Dry-fit to ensure proper seating; do not over-apply sealants unless specified by the service manual.
- Tighten housing bolts to factory torque in a crisscross pattern.
- Refill and bleed coolant; check for leaks at operating temperature.
Why Buy From CPP Diesel
- ESN-verified fitment support from diesel specialists
- Fast shipping and easy returns
- Deep inventory of complementary Cummins B-Series parts
FAQ
Does this fit both 5.9L and 6.7L Cummins?
Yes—if your application specifies Cummins 3954829. Verify by ESN or OEM parts catalog to be certain.
Do I need sealant?
Most applications use the seal dry on clean surfaces. Follow the Cummins service manual for your ESN.
When should I replace this seal?
Any time the thermostat or housing is removed, or if you see evidence of seepage around the joint.
