Product Description
The Cummins 3931523 OEM Fuel Lift Pump Elbow Hose is the factory-molded fuel pre-heater-to-lift-pump hose used on 1994–1998 Dodge Ram 2500/3500 trucks with the 5.9L 12-valve Cummins. This short molded elbow replaces cracked, swollen, or seeping originals that can introduce air into the fuel system and cause hard starts, low power, and random stalling. As a genuine Cummins B-series fuel hose, it matches the OE geometry, rubber compound, and internal diameter so your P7100-equipped 12-valve primes quickly and maintains solid fuel supply to the mechanical lift pump.
Positioned between the fuel pre-heater and the mechanical lift pump inlet, this elbow sees constant heat cycling and fuel exposure. Cheap straight hose and hardware-store elbows kink easily and often fail in a few months. The 3931523 molded elbow restores proper routing and flow while eliminating the hidden air leaks that plague aging 12-valve trucks. Pair it with fresh Cummins hard lines and seals from CPP Diesel to fully refresh your 94–98 fuel supply side.
Fitment
- 1994–1998 Dodge Ram 2500, 5.9L 12-valve Cummins (6BT, P7100 mechanical injection)
- 1994–1998 Dodge Ram 3500, 5.9L 12-valve Cummins (6BT, P7100 mechanical injection)
- Location: Fuel pre-heater outlet to mechanical lift pump inlet (heater-to-lift-pump molded elbow)
- Cummins B-Series Tier 1 5.9L industrial/off-highway applications using hose P/N 3931523 (verify by ESN)
Why Choose Genuine Cummins 3931523 from CPP Diesel?
- True OEM Cummins hose – not a generic parts-store elbow or straight hose workaround.
- Correct molded geometry prevents kinking and rubbing on nearby components.
- Engineered rubber compound for diesel fuel and under-hood temperature exposure.
- Fixes common hard-start and aeration issues caused by tiny cracks and air leaks in the original hose.
- Matched to other genuine Cummins lines like 3918880 and 3923090 for a complete fuel supply refresh.
- Backed by CPP Diesel with expert 5.9L Cummins support and fast shipping.
Cross-Reference / Related Cummins Parts on CPP Diesel
For a complete, leak-free 12-valve fuel supply system, pair this hose with these genuine Cummins components:
- CUMMINS 4988747 OEM MECHANICAL FUEL TRANSFER LIFT PUMP – 5.9L 12V (1994–1998) – factory-style mechanical lift pump that this elbow feeds.
- CUMMINS 3914284 OEM LIFT PUMP SPACER PLATE – 12-VALVE 5.9L (1994–1998) – required when deleting the stock fuel pre-heater/strainer assembly.
- CUMMINS 3918880 OEM FUEL SUPPLY TUBE (LIFT PUMP TO FILTER) – RAM 5.9L 12V (1994–1998) – OE hard line from lift pump outlet to fuel filter inlet.
- CUMMINS 3923090 OEM FUEL SUPPLY LINE TO FUEL PRE-HEATER – RAM 5.9L 12V (1994–1998) – OE supply line feeding the pre-heater on 12-valve trucks.
- CUMMINS 3923171 OEM FUEL INJECTION PUMP RETURN LINE (FUEL DRAIN TUBE) – RAM 5.9L 12V (1994–1998) – factory return/drain tube from the P7100 injection pump.
- CUMMINS 3928898 OEM P7100 INJECTION PUMP SUPPORT BRACKET – RAM 5.9L 12V (1994–1998) – OE brace to stabilize the P-pump and protect lines and hoses.
Specifications for cummins 3931523
| Parameter | Value |
|---|---|
| Brand | Cummins (Genuine OEM) |
| Part Number | 3931523 |
| Replaces / Cross Ref | Cummins 3921680 (earlier heater-to-lift-pump hose) |
| Application | Fuel pre-heater outlet to mechanical lift pump inlet on 5.9L 12V B-series |
| Engine Coverage | 5.9L 12-valve Cummins (1994–1998 Ram 2500/3500), select Tier 1 5.9L B-series |
| Hose Type | Molded fuel elbow hose, approx. 1/2" ID |
| UPC | Not specified by manufacturer |
| GTIN | Not specified by manufacturer |
| Shipping Weight | ~0.06 lb (0.03 kg) |
| Package Dimensions | Approx. 3.3 in x 3.35 in x 1.2 in |
| Hazard Class | Non-Hazardous (NOI, ICE/Auto) |
| E-Codes | N/A (standard service part) |
| Prop 65 | WARNING: Cancer and Reproductive Harm – www.P65Warnings.ca.gov |
| Shipping Info | Ships from CPP Diesel; shipping calculated at checkout |
FAQ
WILL THIS HOSE FIT MY 1994–1998 DODGE RAM 5.9L 12-VALVE?
Yes. Cummins 3931523 is the correct molded elbow that connects the factory fuel pre-heater outlet to the mechanical lift pump inlet on 1994–1998 Dodge Ram 2500/3500 trucks with the 5.9L 12-valve Cummins and P7100 injection pump. Always verify by VIN or engine serial number if your truck has been modified.
DOES THIS HOSE REPLACE THE ORIGINAL HEATER-TO-LIFT PUMP HOSE?
Yes. This is the genuine Cummins replacement for the OE heater-to-lift-pump elbow hose and supersedes earlier part numbers, including 3921680. If your original hose is soft, cracked, or fuel-soaked, this is the correct OEM fix.
CAN A GENERIC STRAIGHT HOSE OR UNIVERSAL ELBOW WORK HERE?
Universal hose may physically connect the fittings but often kinks, rubs, or leaks because it does not follow the factory bend profile. The molded 3931523 elbow is shaped specifically for the 12-valve fuel system, providing proper routing, clearance, and long-term durability.
WHAT OTHER PARTS SHOULD I REPLACE WHILE I’M IN THERE?
For best results, pair this elbow with a new mechanical lift pump (Cummins 4988747), fresh hard lines like 3918880 and 3923090, and new sealing washers as required. Many owners also install a new fuel filter at the same time to minimize contamination and reduce priming time after service.
HOW DO I KNOW IF THIS HOSE IS CAUSING HARD STARTS OR AIR IN THE SYSTEM?
Symptoms often include extended crank time after sitting, visible fuel seepage around the hose, wet hose ends, or bubbles in a clear supply line. Because this elbow sits in a hot zone and is over 25 years old on most trucks, replacing it with a genuine Cummins hose is inexpensive insurance against air intrusion.
