Product Description
Cummins 3957081 — #1 Fuel Injection Line / Injector Fuel Supply Tube for ISB 5.9L
MPN: 3957081 | Also Known As: fuel injection line, injector fuel supply tube | Position: Cylinder #1 (front)
Why This Part
- ✓ OE high-pressure line from common rail to injector #1.
- ✓ Direct-fit for 2003–2007 Ram 5.9L ISB (24V common-rail).
- ✓ Restores safe, leak-free fuel delivery and rail pressure.
- ✓ Genuine Cummins tubing, bends, and flare geometry.
Quick Specs
| Type | Injector fuel supply tube / high-pressure line |
|---|---|
| OE Part # | 3957081 (Cylinder #1) |
| Qty Required | 1 per engine (for cyl. #1) |
| Construction | Precision-bent steel line with OE fittings |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 2003–2007 | Ram 5.9L ISB (24V Common-Rail) | Ram 2500/3500 |
Industrial/Off-Highway: Cummins denotes usage on certain ISB/QSB applications; confirm by ESN for non-automotive engines.
Often Paired With
- Other 5.9L lines: #2 (4988810), #3 (4988809), #4 (5289447), #5 (4988807), #6 (4988806)
- Injector connector tube & seals (recommended if disturbed)
- Fuel system cleaning if contamination was present
What’s In The Box
- (1) Genuine Cummins Injector Fuel Supply Tube / Line — Cylinder #1 (3957081)
Install Tips
- Cleanliness is critical; cap open ports and lines during service.
- Start fittings by hand to avoid cross-threading; torque per factory spec.
- Do not bend or reuse damaged high-pressure lines; check for leaks on first start.
FAQ
WILL THIS FIT MY 2003–2007 5.9L CUMMINS RAM?Yes—3957081 is the OE high-pressure line for cylinder #1 on 2003–2007 5.9L ISB (24V common-rail) Ram 2500/3500. Verify by VIN/ESN if components have been changed.
IS THIS THE RAIL-TO-INJECTOR LINE OR THE CONNECTOR TUBE?This is the rail-to-injector high-pressure line for cylinder #1. The connector (feed) tube and seals are separate parts.
CAN I REUSE MY OLD HIGH-PRESSURE LINE?Reuse is not recommended. Lines can work-harden, deform at the sealing cone, or develop leaks. Replace if removed or damaged.
WHAT ARE THE PART NUMBERS FOR THE OTHER CYLINDERS?#2: 4988810, #3: 4988809, #4: 5289447, #5: 4988807, #6: 4988806.
IS THIS A GENUINE CUMMINS PART?Yes—OE Cummins line with factory bends and fittings for proper sealing.
