WnSEu LS Throttle Body Bypass Hose Kit — Steel‑Braided Crossover for GM LS Engines, Front/Rear Install

WnSEu's LS Throttle Body Bypass Hose Kit provides a complete, reusable coolant/steam crossover solution for GM LS-series engines to route coolant between head ports without using intake manifolds.

This kit supplies the parts needed to connect the coolant/steam ports on LS-series cylinder heads when your intake manifold doesn’t provide a built-in crossover passage. It’s designed for straightforward installation on either the front or rear of the heads, includes sealing hardware and a steel-braided hose, and works across the GM LS family of engines. Note: this kit is not compatible with FAST 102 intake manifolds, and thread sealant is not supplied.

How does this kit replace an intake manifold crossover?

The kit gives you an external path for coolant to move between the cylinder head ports that an intake crossover would normally provide. This is useful when swapping manifolds, running aftermarket throttle bodies, or repairing a damaged internal passage.

• Supplies a steel-braided hose to bridge the two head ports.
• Includes two coolant port fittings and mounting bolts for secure attachment.
• Two O-rings ensure a reliable seal at each port when installed correctly.

What parts are included and why they matter?

The kit bundles the essential components so you don’t have to source fittings separately. Each item is selected to provide a durable, serviceable connection that resists vibration and engine bay heat.

• Two O-rings: create the primary seal between the fittings and head ports.
• Two bolts: fasten the fittings to the cylinder heads securely.
• Two coolant ports (fittings): threaded connectors that mate to the head openings.
• One steel-braided hose: flexible, abrasion-resistant bridge for coolant flow.
• PTFE thread tape: helps seal the threaded joints during assembly.

Where can this kit be installed on the engine?

The bypass hose kit is adaptable to either the front or rear pair of coolant/steam ports on LS-series heads. That flexibility makes it suitable for many intake and throttle-body configurations where an internal crossover is absent or undesired.

• Front or rear head installation capability depending on your manifold layout.
• Works with any GM LS-series engine family member for broad compatibility.
• Not recommended for engines using FAST 102 style intake manifolds.

How should I prepare and install the kit for best results?

Clean the head port faces and verify thread engagement before assembly. Use the included PTFE tape on threaded joints and replace O-rings if damaged; keep thread sealant on-hand because it isn’t supplied with the kit.

• Inspect and clean both head ports to remove old sealant or debris.
• Wrap threads with the supplied PTFE tape and install fittings hand-tight before torqueing to spec.
• Verify O-ring seating and test for leaks after the engine reaches operating temperature.

Who this is for: This WnSEu LS Throttle Body Bypass Hose Kit is aimed at mechanics, engine builders, and LS swap enthusiasts who need a reliable external coolant crossover. It’s ideal when using aftermarket intakes or throttle bodies that remove the stock crossover, when replacing damaged internal passages, or when a quick, serviceable solution is preferred. If you plan to use a FAST 102 intake manifold or require factory internal passages, choose a different solution.