Product Description
Interstate-McBee M-3909696 Fuel Injector Return Manifold (Return Line) – 1989–1993 5.9L Cummins 12-Valve
Restore proper injector leak-off flow on your first-gen Cummins. The Interstate-McBee M-3909696 fuel injector return manifold is a direct-fit replacement for 1989–1993 5.9L 12-valve (6BT) applications, installing in the factory routing to maintain OE function and reliability.
- Direct-fit replacement: Installs in the OEM location with OE-style geometry for correct routing.
- OE function: Maintains proper injector leak-off/return to prevent seepage and air intrusion.
- Aftermarket value: Interstate-McBee quality at significant savings vs. OEM box pricing.
- Application-specific: Designed for 1989–1993 Dodge Cummins 5.9L 12V (6BT) platforms.
Specifications
| Manufacturer | Interstate-McBee |
|---|---|
| Part Number | M-3909696 |
| OEM Reference | Cummins 3909696 |
| Function | Fuel injector return manifold (injector leak-off line) |
| Engine | 5.9L Cummins 12-Valve (6BT) |
| Applicable Years | 1989–1993 |
| Warranty | Fuel injection parts typically covered for 12 months from installation (see manufacturer policy). |
What's Included
- (1) Fuel injector return manifold/line assembly
Banjo bolts and sealing washers are not included and should be replaced during service.
Vehicle Fitment
For best results, verify using your engine serial number (ESN).
- Dodge (First-Gen) 5.9L Cummins 12-Valve (6BT)
- 1989–1993 D/W-Series 250 & 350 (commonly referred to as “’89–’93 Dodge Cummins”)
Helpful Install Notes
- Work on a cool engine; clean the area to prevent debris from entering fittings.
- Replace copper sealing washers on injector banjo bolts to ensure a leak-free seal.
- Prime the fuel system per service manual after installation and inspect for seepage.
Why Buy From CPP Diesel
- First-gen Cummins specialists with ESN-verified fitment support.
- Fast shipping and easy returns to keep your truck on the road.
- Deep catalog coverage for B-Series fuel, gasket, and timing components.
FAQ
Will this fit all 1989–1993 5.9L Cummins trucks?Yes—this line is listed for first-gen 1989–1993 5.9L 12-valve Cummins applications. Verify by ESN for edge cases or swapped components.
Does it include banjo bolts or sealing washers?
No—the manifold/line only. We recommend installing new sealing washers and inspecting banjo bolts for damage during service.
How does Interstate-McBee compare to a genuine Cummins part?
Interstate-McBee builds to OEM-equivalent form, fit, and function at a lower price point. If an OEM-boxed part is required, Cummins 3909696 is the genuine number.
What symptoms indicate a failing return manifold?
Fuel seepage around injector leak-off fittings, hard restarts due to air entry, or a line that cracks when disturbed are common signs.
What is the warranty on this fuel injection part?
Fuel-injection category parts from Interstate-McBee are generally covered for 12 months from first installation. Check current manufacturer policy for specifics.
Product Videos
Custom Field
YEAR 1989-1993
MAKE DODGE
ENGINE 5.9L
