Hybrid Racing K Series Adjustable Thermostat Housing

Hybrid Racing Swivel Neck Thermostat Housing - K20 & K24

If you've ever had a thermostat neck point the wrong direction for your radiator, you already know why this exists. Between swaps, aftermarket radiators, and every hose routing under the sun, the factory housing puts the outlet where Honda wanted it and that's that. Ours swivels a full 360 degrees, so you point the outlet wherever your build needs it and stop fighting your own coolant plumbing. It's machined from billet aluminum, finished in black anodize, and built to OEM quality standards because a thermostat housing is not a part you want to think about twice.

The Swivel Neck Is The Whole Point

The main housing uses a -16 ORB thread, and that's what gives you the rotation. Spin it to any angle, tighten it down, and run whatever you want off it. You can go with an OEM-style radiator hose or step up to an AN fitting if your build is plumbed that way. That flexibility is the difference between a housing that works with your radiator and one that dictates what radiator you can use. On a K-swap especially, where the engine and the chassis were never designed to go together, being able to aim the outlet exactly where you need it saves you from creative hose routing you'll regret later.

Why We Built This In The First Place

Customers asked us for this for years, and the reason is the aftermarket alternatives. Most of what's out there ships with a generic thermostat that either leaks, doesn't open properly, or opens at a temperature nowhere near OEM spec. That's a bad trade on a part responsible for your engine's cooling. So we built the housing to OEM quality and put a real thermostat in it, and we include an OEM-style O-ring so it seals the way it should instead of weeping coolant onto your block. It's the reliable version of a part that a lot of companies treat as an afterthought.

Standard Or HYPERCOOL Low Temp?

You've got two thermostat options, so pick based on your build rather than assuming colder is better.

The standard OEM K-series thermostat opens at 172.4 degrees, which is factory spec. That means factory functionality, factory warm-up behavior, and factory reliability. If your car is stock, mildly modified, or a daily driver, this is the right choice and there's no reason to complicate it.

The HYPERCOOL low temp thermostat fully opens roughly 18 degrees sooner, so coolant starts circulating earlier and the engine spends less time creeping up in temp. That's genuinely useful on a boosted or hard-driven car where you're fighting heat, and it gives your cooling system a head start before things get hot. Worth being straight about what it isn't, though: opening sooner doesn't fix an undersized radiator or a car that's actually overheating. It buys you margin, it doesn't manufacture cooling capacity. And on a cold-climate daily, the engine will take a bit longer to reach operating temp. If you're chasing heat on a built car, run the HYPERCOOL. If not, the standard is the smarter pick.

An Extra Port For Your Sensor

There's a single threaded M18x1.5 port up top, and it's more useful than it sounds. Anyone running a standalone ECU, a gauge, or an aftermarket coolant temp sensor needs somewhere clean to put it, and this gives you a proper location instead of a tee fitting spliced into a hose. If you don't need it, it's plugged and out of the way. If you do, it's already there waiting.

Fits Your K-Series

This housing fits all K20A and K20Z thermostat bases and K24A series bases, which covers a wide swath of Honda and Acura:

It also fits K-swaps built around these engines, since it mounts to the thermostat base rather than the chassis. If you're running a K20 or K24, this works.

Who Should Run This Housing

This is for the K-series owner who's tired of working around the factory neck, or who's replacing a tired housing and would rather put something better on than the same plastic-and-luck setup. Swap builders get the routing freedom, boosted cars get the low temp option, and everybody gets a part that seals properly and looks right doing it. Pick your thermostat, point the neck where you need it, and stop thinking about your coolant plumbing.

Fits: all K20A / K20Z thermostat bases and K24A series bases, across the models above, plus K-swaps. Construction: billet aluminum, black anodized. Outlet: -16 ORB thread, rotates 360 degrees, works with OEM-style hose or AN fitting. Sensor port: M18x1.5, single threaded. Thermostat options: OEM standard (opens 172.4°F) or HYPERCOOL low temp (fully opens roughly 18°F sooner). Includes: OEM-style O-ring.