Product Description
CUMMINS 3912977 OEM ELBOW HOSE COUPLING – RAM 5.9L (1989–1998)
The CUMMINS 3912977 OEM elbow hose coupling is a factory-correct 90° connection fitting used in the heater and coolant plumbing on 1989–1998 5.9L Cummins engines. This elbow links heater hoses and coolant tubes in the factory layout, maintaining a secure, leak-free connection that resists vibration, corrosion, and thermal cycling. If your original elbow is rusted, seized, or leaking, replacing it with a genuine Cummins component restores proper cooling system reliability.
Constructed from high-strength materials and engineered for OE fitment, this coupling integrates perfectly with the B-series coolant system—including heater core lines, metal coolant tubes, and block-mounted fittings. Avoid coolant leaks and premature hose wear by installing the correct Cummins elbow instead of generic hardware-store fittings.
Key Features
- Genuine Cummins OEM fitting – correct bend, diameter, and engagement depth.
- Designed for heater/coolant tube connections on 1989–1998 5.9L Cummins engines.
- Corrosion-resistant construction to withstand long-term coolant exposure.
- Precision-machined for a leak-free attachment.
- Direct replacement for cracked, rusted, or leaking elbows.
Fitment Details
- Engine: 5.9L Cummins 12-Valve (1989–1998)
- Chassis: Dodge Ram 2500 / 3500 (1st & 2nd Gen)
- Function: Heater/coolant hose elbow coupling
- Notes: Always confirm hose and tube routing by VIN/ESN.
Cross-Reference & Companion Cummins Parts
CPP Diesel carries matching coolant and heater tube components that pair with CUMMINS 3912977, including:
- CUMMINS 3912087 INNER HEATER TUBE – 5.9L 12V
- CUMMINS 3916127 WATER INLET TUBE – 5.9L CUMMINS
- CUMMINS 3283581 WATER OUTLET CONNECTION – 5.9L
- VIEW ALL GENUINE CUMMINS OEM PARTS
Common Cummins cross-reference numbers: 3912977, 3912977-0, 3906698 (verify by VIN/ESN).
Installation Notes
- Inspect heater hoses for cracks before reinstalling.
- Use appropriate coolant-safe thread sealant if required by application.
- Ensure the elbow is fully seated to prevent leaks.
- Pressure-test the cooling system after installation.
Specifications for cummins 3912977
| Attribute | Value |
|---|---|
| Brand | Cummins (Genuine OEM) |
| Cummins Part Number | 3912977 |
| Alternate / Cross Reference | 3906698, 3912977-0 (verify by VIN/ESN) |
| Function | Heater/coolant hose elbow coupling |
| Engine Compatibility | 5.9L Cummins 12-Valve (1989–1998) |
| Vehicle Fitment | 1989–1998 Dodge Ram 2500 / 3500 |
| UPC | 190910244962 |
| GTIN | 190910244962 |
| Shipping Weight | Approx. 0.20 lbs |
| Shipping Method | Standard ground shipping; expedited available |
| E-Codes / Emissions | Not emissions related |
| Prop 65 Warning | WARNING: May expose you to chemicals known to the State of California to cause cancer and reproductive harm. Visit www.P65Warnings.ca.gov. |
| Country of Origin | As labeled by Cummins (varies by lot) |
Frequently Asked Questions
WILL THIS FIT MY 1989–1998 5.9L CUMMINS?
Yes. CUMMINS 3912977 is used on most 12-valve 5.9L heater/coolant tube systems from 1989–1998. Always verify by VIN/ESN.
WHAT HOSES CONNECT TO THIS ELBOW?
This elbow typically connects heater hoses and coolant tubes such as the CUMMINS 3912087 INNER HEATER TUBE.
IS THIS METAL OR PLASTIC?
The Cummins OEM elbow is a high-durability metal fitting, engineered to withstand heat and vibration.
IS THIS A GENUINE CUMMINS PART?
Yes — this is a factory-original Cummins OEM fitting sourced by CPP Diesel.
