Billet Technology Water Neck 392 6.4L Hemi

Eliminate Coolant Leaks Before They Start with a Billet Water Neck

The Billet Technology 300222 Billet Aluminum Water Neck replaces the factory plastic or OEM water neck (thermostat outlet housing) with a precision CNC-machined billet aluminum piece on your 2011-2024 Chrysler 300, Dodge Challenger, Dodge Charger. The factory water neck on these high-output 6.4L 392 HEMI engines is a known weak point that warps and develops coolant seepage under the repeated thermal cycling of hard driving. The 300222 is CNC machined in Lake Worth, Florida from solid 6061-T6 certified domestic aircraft-grade aluminum, delivering a permanent solution that also adds a premium machined appearance to the engine bay. Direct bolt-in fit, OEM gasket compatible, no modifications required.

Key Features

• Precision CNC machined from solid 6061-T6 certified domestic aircraft-grade aluminum
• Engineered as a direct replacement for the factory water neck on the 6.4L 392 HEMI
• Eliminates the OEM plastic or cast iron water neck that is prone to warping, cracking, and coolant seepage under high operating temperatures
• Machined coolant passage geometry matches OEM flow characteristics
• Available in satin finish
• Billet Technology 300222 is backed by a limited lifetime warranty against defects in materials and workmanship
• Made in the USA

Fitment

Specifications

What Is Included

• 1x Billet Technology 300222 Billet Aluminum Water Neck
• Gasket set (verify on product page , select versions include gasket)
• Installation hardware

Frequently Asked Questions

Does the Billet Technology 300222 water neck require a new thermostat?

The 300222 accepts the OEM thermostat. You can reuse your existing thermostat or install a new OEM-spec thermostat at the time of installation. Refer to the factory service manual for the correct thermostat specification.

Does the billet water neck use OEM gaskets?

Yes. The this product is machined to accept OEM gaskets or an OEM-equivalent gasket set. Use a fresh gasket at installation. Some kits include a gasket , refer to the What Is Included section.

Will the billet water neck improve cooling performance?

The this product is a direct replacement with matched coolant passage geometry. While it does not alter thermostat opening temperature, eliminating the factory housing material's tendency to warp ensures consistent thermostat seating and coolant flow.

Is the this product compatible with OEM and aftermarket coolants?

6061-T6 aluminum is compatible with standard ethylene glycol and OAT-based coolants. Do not mix coolant types. Flush the system if switching coolant formulas.

Does this water neck fit both the Charger and Challenger?

Both vehicles share the same engine family. Refer to the fitment table for exact year and model compatibility.

What torque specification should I use for the water neck bolts?

Torque fasteners to the OEM specification listed in the factory service manual for the 6.4L 392 HEMI. Over-torquing can crack the housing flange.

Is the Billet Technology water neck made in the USA?

Yes. The this product is CNC machined in Lake Worth, Florida from certified domestic 6061-T6 aluminum.

Do I need to bleed the cooling system after replacing the water neck?

Yes. Any time the cooling system is opened, air pockets can form. Fill the system, run the engine to operating temperature, check for leaks, and top off the coolant level after the thermostat opens.

Installation Instructions

1. Allow the engine to cool completely. Never work on a hot cooling system.
2. Place a drain pan under the vehicle and drain the coolant by loosening the lower radiator hose or drain petcock.
3. Disconnect the radiator hose, heater hose, and any other coolant lines attached to the factory housing.
4. Remove the OEM fasteners securing the factory thermostat housing.
5. Remove the factory housing and thermostat. Clean the mating surface thoroughly.
6. Install a fresh gasket on the Billet Technology this product billet housing.
7. If reusing the OEM thermostat, verify it is in good condition. Install the thermostat into the billet housing.
8. Mount the 300222 to the engine block mating surface and torque fasteners to OEM specification.
9. Reconnect all coolant hoses and secure with OEM-style clamps.
10. Fill the cooling system with the correct coolant type and bleed all air from the circuit.
11. Start the engine, bring to operating temperature, and check for leaks.
12. Top off coolant level after the thermostat opens and recheck after first heat cycle.

WARNING: This product can expose you to chemicals including lead and phthalates, which are known to the State of California to cause cancer and reproductive harm. For more information go to www.P65Warnings.ca.gov.