Product Description
Genuine Cummins
Cummins 3906697 — Water Inlet Connection Seal (Rectangular Ring O-Ring)
MPN: 3906697 | Also Known As: lower radiator inlet adapter seal, water inlet O-ring, rectangular ring | Cross-Refs (ID): 3901467, 4983908
Why This Part
- ✓ OE sealing ring for the water inlet connection elbow at the engine block.
- ✓ Direct-fit for Dodge/Ram 5.9L & 6.7L Cummins (1994–2025; verify by VIN/ESN).
- ✓ Stops coolant seep/leaks at the lower radiator inlet adapter.
- ✓ Built to Cummins specifications for long service life.
OE Fit Stock Replacement 1 Per Engine
Quick Specs
| Type | Rectangular ring seal (water inlet connection O-ring) |
|---|---|
| OE Part # | 3906697 |
| Location | Water inlet elbow / lower radiator inlet adapter to engine block |
| Qty Required | 1 per engine (sold individually) |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 1994–2002 | Ram 5.9L Cummins (12V/24V) | Ram 2500/3500 |
| 2003–2007 | Ram 5.9L ISB (24V Common-Rail) | Ram 2500/3500 |
| 2007.5–2025 | Ram 6.7L ISB (24V Common-Rail) | Ram 2500/3500 |
Industrial/Off-Highway: Common on 4BT/6BT/ISB/QSB applications (verify by ESN for exact adapter style before ordering).
Often Paired With
- Lower radiator inlet adapter/elbow (engine-side)
- Thermostat & housing gasket (if servicing cooling system)
- Fresh coolant after reassembly and bleed
What’s In The Box
- (1) Genuine Cummins Rectangular Ring Seal / Water Inlet O-Ring (3906697)
- Other gaskets/hardware sold separately.
Install Tips
- Clean both sealing surfaces; remove old seal and residue.
- Lightly lube with coolant-safe lubricant; seat evenly.
- Torque housing/adapter bolts to spec in a cross pattern; bleed cooling system and check for leaks.
FAQ
WILL THIS FIT MY 5.9L OR 6.7L RAM?Yes—designed for the water inlet connection on 5.9L (1994–2007) and 6.7L (2007.5–2025) Ram diesels. Always verify by VIN/ESN.
WHERE DOES THIS SEAL INSTALL?Between the lower radiator inlet adapter (water inlet elbow) and the engine block.
HOW MANY DO I NEED?One per engine. Replace any time the adapter is removed or a leak is present.
IS THIS A GENUINE CUMMINS PART?Yes—OE Cummins 3906697 rectangular ring seal.
DOES THIS ALSO FIT INDUSTRIAL ENGINES?Common across 4BT/6BT/ISB/QSB variants that use the same adapter design; confirm by ESN.
Product Videos
Custom Field
Vehicle Year 1989,1990,1991,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,2002,2003,2004,2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018
Vehicle Make DODGE
ENGINE 5.9L,6.7L
Part Type Water Inlet Connection Rubber O Ring
