Product Description
Genuine Cummins
Cummins 3957079 — Fuel Rail Supply Line (CP3 Pump to Rail)
MPN: 3957079 | Also Known As: fuel supply tube, high-pressure line, CP3-to-rail tube | Cross-Ref: Mopar 5086870AA
Why This Part
- ✓ OE high-pressure line from CP3 pump to common rail for proper sealing and flow.
- ✓ Direct-fit for 2003–2007 Ram 5.9L ISB (verify by VIN/ESN).
- ✓ Corrosion-resistant steel construction for durability under pressure and heat.
- ✓ Ideal when replacing a contaminated or leaking CP3-to-rail tube.
OE Fit High Pressure 1 Per Engine
Quick Specs
| Type | Fuel rail supply line (CP3 to rail), high-pressure |
|---|---|
| OE Part # | 3957079 (cross-ref Mopar 5086870AA) |
| Qty Required | 1 per engine (sold individually) |
| Fuel | Diesel (common-rail) |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 2003–2007 | Ram 5.9L ISB (24V Common-Rail) | Ram 2500/3500 |
Notes: Automotive use is 2003–2007 5.9L CP3-to-rail line. Always verify by VIN/ESN and rail/pump configuration.
Often Paired With
- Fuel Rail (Bosch): 0445226014
- Fuel Rail Return Line (Mopar): 05086810AA
- High-pressure injector lines (#1–#6): model-year specific
What’s In The Box
- (1) Genuine Cummins Fuel Rail Supply Line (3957079)
- Related hardware/lines sold separately (see “Often Paired With”).
Install Tips
- Work clean—any debris in an HPCR system can damage injectors.
- Torque fittings to spec; do not overtighten flare seats.
- After installation, prime and check for leaks at idle and under load.
FAQ
WILL THIS FIT MY 2003–2007 5.9L CUMMINS RAM?Yes—3957079 is the OE CP3-to-rail line for 2003–2007 5.9L ISB Ram 2500/3500 (verify by VIN/ESN).
WHAT DOES THIS LINE CONNECT?It connects the high-pressure outlet of the CP3 pump to the common fuel rail.
WHAT’S THE MOPAR CROSS-REFERENCE?Mopar 5086870AA is a documented cross-reference used by many catalogs.
CAN I REUSE OLD FITTINGS OR SEALS?Do not reuse damaged fittings. Always inspect sealing surfaces and replace any questionable hardware.
HOW DO I PREVENT CONTAMINATION?Cap all open lines/ports during service. Flush if the system saw rust or debris before reassembly.
Product Videos
Custom Field
Vehicle Year 2003,2004,2005,2006,2007
Vehicle Make DODGE
ENGINE 5.9L
