Product Description
The Cummins 3926103 OEM fuel injector return line is the correct leak-off / overflow manifold for 1994–1998 Dodge Ram 2500/3500 trucks equipped with the 5.9L 12-valve Cummins and Bosch P7100 injection pump. This genuine Cummins line restores proper return fuel flow across all six injectors, helps eliminate annoying diesel drips and aeration in the fuel system, and keeps your 12-valve running clean, quiet, and reliable the way it was designed.
Unlike cheap aftermarket tubes that don’t seal correctly or crack at the fittings, this genuine Cummins manifold, fuel (3926103) is formed to OEM specs for the 12-valve B-series. It drops right in place on the injector tops, maintains the correct routing and clamp locations, and pairs perfectly with OEM banjo bolts and sealing washers. If you’re chasing hard starts, fuel smell on the manifold, or mystery wet spots around the injector lines, replacing this return manifold with a real Cummins part is a smart, once-and-done fix.
Fitment – Cummins 3926103 Fuel Injector Return Line
- Engine: 5.9L Cummins 12-valve (inline Bosch P7100)
- Vehicle: Dodge Ram 2500/3500
- Model Years: 1994, 1995, 1996, 1997, 1998 (12-valve only, not 1998.5+ 24V)
- Function: Injector overflow / leak-off manifold fuel return line
- Position: Connects the six injector leak-off ports to the return circuit
Note: This part is specific to the 12-valve P-pump platform. It does not fit 1989–1993 VE-pump trucks or 1998.5–2002 24-valve VP44 applications.
Recommended OEM Companion Parts (Cummins Only)
For a complete 12-valve fuel line refresh, pair Cummins 3926103 with these other genuine Cummins lines and hardware available from CPP Diesel:
- Cummins 3923090 OEM Fuel Supply Line to Fuel Pre-Heater – 5.9L 12V
- Cummins 3918880 Fuel Supply Tube (Lift Pump to Filter) – 5.9L 12V
- Cummins 3866798 OEM Injector Fuel Supply Line Set – 5.9L 12V (Bosch P7100)
- Cummins 3923171 OEM Fuel Injection Pump Return Line (Fuel Drain Tube) – 5.9L 12V
- Cummins 3905307 OEM Fuel Injector Return Line Banjo Bolt – 5.9L 12V
- Cummins 4942278 OEM Fuel Injector Return Line Banjo Seal (Washer) – 5.9L 12V
When you combine the 3926103 return manifold with these supply and drain lines, you renew the entire hard-line side of the 12-valve fuel system from tank to injector, which is a huge win for leak-free operation, easier priming, and long-term reliability.
Why Buy Your Cummins 3926103 from CPP Diesel?
- Genuine Cummins OEM part – no knockoffs or white-box substitutions
- Specialized in Dodge Cummins performance and OEM replacement
- Fast shipping and careful packaging to protect the formed line
- Enthusiast support from people who actually work on 12-valve trucks
Specifications for cummins 3926103
| Attribute | Value |
|---|---|
| Brand | Cummins (Genuine OEM) |
| Part Number | 3926103 |
| UPC | 607605786867 |
| GTIN | 607605786867 |
| Product Description | MANIFOLD, FUEL – Injector overflow / leak-off return line |
| Engine Compatibility | 5.9L Cummins 12-valve B-series with Bosch P7100 injection pump |
| Vehicle Fitment | 1994–1998 Dodge Ram 2500/3500 with 5.9L 12V Cummins (P-pump) |
| Cross Reference / Related Cummins Lines | 3923090 Fuel Supply Line to Pre-Heater, 3918880 Fuel Supply Tube (Lift Pump to Filter), 3866798 Injector Fuel Supply Line Set, 3923171 Fuel Injection Pump Return Line, 3905307 Banjo Bolt, 4942278 Banjo Seal Washer |
| E-Codes / Emissions | Not specifically listed – used on B-series 5.9L applications; verify by ESN if needed |
| Shipping Info | Ships from CPP Diesel via standard ground service; expedited options available at checkout |
| Country of Origin | As stamped on part or Cummins packaging (varies by batch) |
| California Prop 65 | WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov . |
Frequently Asked Questions
Will Cummins 3926103 fit my 1994–1998 Dodge Ram 5.9L 12-valve?
Yes. This manifold is the correct OEM fuel injector return line for 1994–1998 Dodge Ram 2500 and 3500 trucks with the 5.9L 12-valve Cummins using the Bosch P7100 injection pump. It will not fit earlier 1989–1993 VE-pump trucks or 1998.5+ 24-valve applications.
What other parts should I replace with this return line?
At a minimum, we recommend installing fresh banjo bolts and sealing washers. CPP Diesel stocks the matching Cummins 3905307 banjo bolts and 4942278 banjo seal washers. Many owners also refresh the 3923090 supply line to pre-heater, 3918880 lift pump to filter tube, 3923171 pump return line, and the 3866798 injector supply line set at the same time.
Is this a genuine Cummins part or aftermarket?
This is a genuine Cummins OEM 3926103 manifold, fuel. CPP Diesel does not substitute off-brand or generic tubes in place of listed Cummins genuine part numbers in the Cummins Genuine Parts product line.
Do I need to modify anything for installation?
No cutting or bending should be required when installed on the correct 1994–1998 12-valve application. Simply remove the old manifold, clean the sealing surfaces, install the new line with fresh banjo bolts and washers, and torque to factory spec. Always verify there are no leaks after priming and initial startup.
How can I confirm this is the correct part for my engine serial number?
The 3926103 manifold is commonly used on B-series 5.9L 12-valve Ram applications, but Cummins occasionally varies hardware by engine serial number (ESN), especially on industrial or marine builds. If you are unsure, contact CPP Diesel with your VIN and, if possible, the Cummins ESN so we can help verify the correct part number before you order.
