Product Description
Cummins 3957290 — Injector Return Check Valve (Back of Cylinder Head)
MPN: 3957290 | Also Known As: fuel return check valve, banjo check valve | Cross-Refs (ID): PAI 042212
Why This Part
- ✓ OE valve that maintains proper injector return pressure and prevents backflow.
- ✓ Direct-fit for 2003–2007 Ram 5.9L ISB (common-rail) on the rear of the cylinder head.
- ✓ Fixes fuel leaks and hot-start issues caused by a worn return check valve.
- ✓ Durable OE construction for reliable sealing and long service life.
Quick Specs
| Type | Injector return (fuel) check valve |
|---|---|
| OE Part # | 3957290 |
| Location | Back of cylinder head on return banjo fitting |
| Qty Required | 1 per engine (sold individually) |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 2003–2007 | Ram 5.9L ISB (24V Common-Rail) | Ram 2500/3500 |
Industrial/Off-Highway: Also used primarily on Tier 3 ISC/ISL 8.9L applications—verify by ESN before ordering.
Often Paired With
- Banjo sealing washers: 12mm (Cummins 3963983) · 14mm (Cummins 3963988) — two per banjo
- Fuel return line (head → filter housing) if lines are aged or damaged
What’s In The Box
- (1) Genuine Cummins Injector Return Check Valve (3957290)
- Washers and line hardware sold separately (see “Often Paired With”).
Install Tips
- Replace both sealing washers (12mm & 14mm) and torque banjo fasteners to spec.
- Clean mating surfaces; inspect the return line for cracks or abrasion.
- Prime fuel system and check for leaks after warm-up.
FAQ
WILL THIS FIT MY 2003–2007 5.9L CUMMINS RAM?Yes—direct-fit OE check valve for 2003–2007 5.9L ISB common-rail Ram 2500/3500 (verify by VIN/ESN).
WHAT WASHERS DO I NEED FOR INSTALLATION?You’ll need one 12mm (Cummins 3963983) and one 14mm (Cummins 3963988) sealing washer at the banjo connections. Replace both; two washers are used per banjo fitting.
WHERE IS THIS VALVE LOCATED?At the back of the cylinder head on the injector return line banjo fitting.
WHAT ARE COMMON FAILURE SYMPTOMS?Fuel seepage at the rear of the head, fuel odor, soft fuel system prime, or hard hot-starts due to return leakdown.
IS THIS A GENUINE CUMMINS PART?Yes—OE Cummins 3957290. PAI 042212 is a common aftermarket cross-reference for identification only.
