You’re flying through your favorite section of the track. The car feels alive, your turbo’s in full song—and then it happens. The temp gauge starts climbing. You back off. Park it. Time to cool off.

Sound familiar?

Overheating is one of the most frustrating issues Miata owners face at the track, especially with iron block turbo setups. It sucks the fun out of the experience and chips away at your confidence in the car.

At R Theory Motorsports, we got tired of watching track sessions end early, so we built a solution that actually solves the problem at its source. Our Coolant Reroute Kit doesn’t just band-aid the issue, it corrects what Mazda should’ve done from the start.

Why Miata Overheating Happens in the First Place

From the factory, coolant enters the front of the cylinder head and exits out the front as well, meaning the rear cylinders (#3 and #4) get the short end of the stick when it comes to heat management. Under daily driving, it’s manageable. But add a turbo and hit the track, and those rear cylinders start to cook.

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Our Fix: A Smarter Coolant Reroute Kit

Our Coolant Reroute Kit for NA and NB Miatas (1.6L and 1.8L) restores proper coolant flow by rerouting it to exit at the rear of the head, exactly how Mazda originally did it on the BP engine in the FWD configurations.

Here’s why our design stands out from the rest:

Engineered for Real-World Install Ease

• Compact, Low-Profile Design means it sits farther from the firewall than other kits, giving you more room to work during install. It’s still tight, but this is about as easy as coolant reroutes get.

• No Rear Bleeder Screw Needed because it’s not the high point in the system, simplifying bleeding and reducing potential leak points.

Designed for Serious Cooling Performance

• Streamlined One-Piece Flow Path avoids the sharp turns and multiple pieces found in other kits, improving coolant velocity and minimizing turbulence.

• 195°F Thermostat Included perfectly balanced for street and track use.

• Silicone Upper Radiator Hose and our custom aluminum S-bend coupler prevent kinks, especially helpful for tight turbo setups.

Built To Last Longer Than Your Miata

• CNC Machined 6061 Aluminum

• Blue Anodized Finish with Laser-Etching

• Integrated 1/8” NPT Port for aftermarket coolant temp sensors

• All hardware included from the block-off plate to the clamps

Note: This kit is not EGR-compatible by design, and we offer EGR block-off plates to complete your performance build.

We Know This Isn’t the Only Cooling Mod You Need, And We’ve Got You Covered

While the coolant reroute is one of the most effective changes you can make, it’s even more powerful when used in tandem with our full suite of Miata cooling upgrades:

• Low Profile Mixing Manifold – Simplifies the coolant path before the water pump, and makes it easier to plumb your turbo's coolant lines.
• Hood Vents (for both NA and NB) – Pull hot air out of the engine bay and reduce underhood temps and front-end lift. Yes, they work. No, they’re not just for looks.
• Upgraded Radiators (NA & NB specific) – Greater core volume, better heat dissipation, and a direct-fit solution that doesn’t compromise.

Whether you’re prepping for your first track day or chasing PBs at time attack events, the R Theory Motorsports Cooling Suite is built to let your Miata breathe, push harder, and stay reliable.

Get Back on the Throttle

This kit was built because we were tired of letting temperature dictate how much fun we could have in our cars. We don’t cut corners, we cut lap times. If you’re serious about driving your Miata the way it was meant to be driven, our Coolant Reroute Kit is the foundation your cooling system needs.

Check Out the R Theory Motorsports Coolant Reroute Kit