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

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