Genuine Bosch high-pressure connector tube for the 5.9L Cummins common rail. This is the steel tube that carries fuel from the rail, through the cylinder head, into the injector, sealing metal-to-metal at both ends. Six are required per engine, one per cylinder.

Fitment

• Dodge Ram 2500 & 3500, 2003–2007, Cummins 5.9L — injectors 0986435503 and 0986435505

2004 is a split year. Check the CPL number on the engine data plate to identify the correct injector: CPL 8213, 8228 or 8412 takes 0986435503; CPL 8346, 8347, 8350 or 8351 takes 0986435505. The connector tube is the same either way.

The 5.9L tube has a smaller inner diameter and a more domed sealing tip than the 6.7L part. A 5.9L tube must never be fitted to a 6.7L engine.

Replaces these part numbers

Cummins 3979419 · Mopar 5086867AA · Mopar 5175565AA · Bosch F00RJ00436 · Bosch F00RJ01224 · 10763 · 522043 · DEC031874 · DIS3

Why it has to be replaced

The sealing tip of a connector tube deforms slightly under torque and takes a permanent impression from the injector it was clamped against. Fit that tube to a new injector and the impression no longer matches, which leaves a leak path at the highest-pressure point in the fuel system. Bosch and Alliant Power both specify replacing all six every time injectors are serviced.

A tube can look perfect and still be finished. What is worn out is a shape you cannot see.

Symptoms of a failed connector tube

• Fuel in the valve cover — the most common sign
• Rising oil level and a diesel smell on the dipstick as fuel dilutes the oil
• Hard starting, particularly when hot
• A miss on one cylinder that follows the tube rather than the injector
• Raw diesel smell after a hard pull with no visible external leak

Warranty and shipping

Valley Fuel Injection has been a Bosch factory-authorized diesel service center since 1993. We ship nationwide from Woodland, California, typically within 1–2 business days. See our warranty terms and shipping policy.

Not sure which tube your engine takes? Call (530) 668-0818 with the year and application and we will confirm it.