Product Description
Cummins 3912977 — Elbow Hose Coupling (Cooling System)
MPN: 3912977 | Also Known As: coolant elbow, hose coupling, lower radiator elbow
Why This Part
- ✓ OE fit & geometry for leak-free coolant connections.
- ✓ Direct-fit for 1989–1998 Ram 2500/3500 5.9L Cummins (see notes below).
- ✓ Durable OE casting and hose sealing surfaces.
- ✓ Restores proper coolant flow after corrosion or damage.
Quick Specs
| Type | Elbow hose coupling (coolant) |
|---|---|
| OE Part # | 3912977 |
| Location | Lower coolant/radiator hose interface (application-dependent) |
| Qty Required | 1 per application (verify by VIN/ESN) |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 1989–1998 | 5.9L Cummins (12-Valve) | Dodge/Ram 2500/3500 |
Compatibility Notes: XDP and CPP list this elbow for 1989–1998 5.9L applications. Some sources show usage into 1994–2002 manual-trans configurations and related elbows like 3912812. Always verify by VIN/ESN and transmission before ordering.
Often Paired With
- Heater Tubes: 3912086 (outer), 3912087 (inner)
- Thermostat & Seal: 180° thermostat and new O-ring
- Hoses & Clamps: lower radiator hose and quality clamps
- Fresh Coolant: refill and properly bleed the system
What’s In The Box
- (1) Genuine Cummins Elbow Hose Coupling (3912977)
- Hoses/gaskets/clamps sold separately (see “Often Paired With”).
Install Tips
- Clean mating surfaces; replace aged hoses/clamps.
- Torque fasteners to spec; check for leaks on warm-up.
- Top off coolant and burp air from the system after installation.
FAQ
WILL THIS FIT MY 1989–1998 5.9L CUMMINS RAM?Yes—this OE elbow is listed for 1989–1998 5.9L (12-valve) Ram 2500/3500 applications. Always confirm by VIN/ESN.
HOW DOES THIS DIFFER FROM THE 3912812 COOLANT ELBOW?3912812 is a related lower engine coolant elbow commonly shown for some 1994–2002 configurations. Use VIN/ESN and transmission to verify which elbow your truck requires.
IS THIS A GENUINE CUMMINS PART?Yes—OE Cummins 3912977 for proper fit and durability.
WHAT ELSE SHOULD I REPLACE WHILE I’M THERE?Inspect and replace aged hoses, clamps, thermostat, and heater tubes (3912086/3912087) as needed to prevent future leaks.
DOES THIS PART FIT INDUSTRIAL B-SERIES ENGINES?Yes—Cummins indicates 3912977 is used primarily on some B-Series applications; verify by engine serial number for industrial/off-highway use cases.
