Product Description
Cummins 3943300 — Vertical Water Neck / Water Outlet Connection
MPN: 3943300 | Also Known As: vertical water neck, water outlet connection | Use Case: straight/vertical upper radiator hose routing (not factory on Dodge/Ram)
Why This Part
- ✓ OE connection for the thermostat housing outlet on ISB platforms.
- ✓ Vertical/straight outlet solves hose routing or swap-clearance needs.
- ✓ Direct bolt-on to ISB 5.9L/6.7L housings (verify hose orientation).
- ✓ Genuine Cummins durability and sealing surfaces to reduce leaks.
Quick Specs
| Type | Vertical water neck / water outlet connection |
|---|---|
| OE Part # | 3943300 |
| Orientation | Straight-up (vertical) outlet |
| 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 |
| 2007.5–2009 | Ram 6.7L ISB (24V Common-Rail) | Ram 2500/3500 |
Notes: This vertical outlet is not factory on Dodge/Ram; it’s commonly used where a straight-up hose connection is desired (swaps, custom routing). Always confirm hose orientation and VIN/ESN before ordering.
Often Paired With
- Thermostat & seal: order a new thermostat seal/O-ring when swapping outlets.
- Upper radiator hose: may require a different hose/clamps for vertical routing.
- Coolant: refill/bleed system after installation.
What’s In The Box
- (1) Genuine Cummins Vertical Water Neck / Water Outlet Connection (3943300)
- Seals/hardware sold separately (see “Often Paired With”).
Install Tips
- Clean mating surfaces; replace the outlet seal/O-ring.
- Torque fasteners to factory spec; check for leaks at warm-up.
- Verify hose routing and clearance with the vertical outlet.
FAQ
WILL THIS FIT MY 2003–2009 RAM 5.9L/6.7L?Yes—3943300 bolts to ISB 5.9/6.7 thermostat housings for 2003–2009. However, it is not the factory outlet on Dodge/Ram; it’s used where a straight/vertical hose connection is desired. Verify hose orientation and VIN/ESN.
IS THIS THE FACTORY WATER NECK?No. It’s a genuine Cummins part, but not factory on Dodge/Ram. It’s commonly used for swaps or when vertical routing is preferred.
DO I NEED A NEW SEAL OR GASKET?Yes. Always install a new thermostat housing seal/O-ring when changing the outlet to prevent leaks.
WILL MY STOCK UPPER RADIATOR HOSE WORK?It may not—vertical outlets often require a different hose and clamps. Check routing before ordering.
IS THIS A GENUINE CUMMINS PART?Yes—OE Cummins 3943300 for proper fit and durability.
