Product Description
Interstate-McBee M-3909696 Fuel Injector Return Manifold – 89-93 5.9 L Cummins 12-Valve
Replacement fuel-return (leak-off) manifold line for early 5.9 L Cummins 12-valve engines used in 1989–1993 Dodge Ram 2500/3500 trucks. This aftermarket manifold distributes excess fuel from the injectors back to the tank and is built to OEM specifications for long-term reliability.
- Direct fit replacement: Bolts into the factory location with correct port spacing.
- OE equivalent quality: Manufactured to match Cummins PN 3909696 specifications.
- Durable construction: Precision-formed steel line with corrosion-resistant plating.
- Budget-friendly: Interstate-McBee quality at aftermarket pricing.
Specifications
| Brand | Interstate-McBee |
| Part Number | M-3909696 |
| OEM Reference | Cummins 3909696 |
| Application | Fuel injector return (manifold line) |
| Material | Steel tube assembly with banjo fittings |
| Sold As | Each (1 manifold line) |
What’s Included
- (1) Fuel injector return manifold line – M-3909696
Vehicle Fitment
Verify fitment by engine serial number (ESN) for best accuracy.
- Dodge Ram 2500 / 3500 – 5.9 L Cummins (12-Valve 6BT)
- Model Years: 1989 – 1993 (first-generation mechanically injected B-series)
- Other 4B / 6B industrial applications using Cummins 3909696 return manifold
Recommended / Related Parts
- Interstate-McBee M-3909414 Fuel Injector (89-93 5.9 L Cummins)
- Interstate-McBee M-3903950 Injector Connector Tube
- Interstate-McBee M-3906208 Fuel Supply Line
- Interstate-McBee M-3905391 Injector O-Ring Kit
Installation Notes
- Always start threads by hand to avoid cross-threading banjo fittings.
- Replace crush washers to prevent leaks at each banjo connection.
- Bleed air from the system after installation before starting engine.
Why Buy From CPP Diesel
- Expert support from Cummins diesel specialists
- Fast shipping and easy returns
- Comprehensive inventory of B-series fuel system components
FAQ
Does this fit 24-valve engines (1998.5 – 2002)?
No, this part fits only the 1989 – 1993 12-valve mechanical injection system.
Is this line pre-bent like OEM?
Yes, it matches OEM geometry and includes correct flare angles and banjo fitting orientation.
Are seals included?
Sealing washers are not included — order separately if your old ones are worn or damaged.
