MX-5 Expansion Tanks

An expansion tank is a part of your car’s cooling system that helps to manage the expansion and contraction of engine coolant, which heats up and cools down while the engine runs.

Simply put, the expansion tank provides a space for the excess coolant to flow into, preventing the build-up of excessive pressure that could cause leaks or damage to the radiator and hoses. 

The expansion tank is usually located near the radiator, connected by a hose. Replacing the stock expansion tank on a race car build is a common upgrade. This is due to increased durability of these tanks (often aluminium), compared to the standard plastic ones — which can degrade, crack and warp under the extreme heat and stress of high-performance racing.

About our range of MX-5 Expansion Tanks

Replacing the stock expansion tank with an aftermarket one will improve cooling efficiency, pressure tolerance and reliability, as well as potentially reducing weight and providing better fitment in a race build. Shop BOFI Racing today to see our wide selection of Mazda MX-5 performance parts. These include the MX-5 Mk1 Moroso expansion tank and the NC coolant expansion tank.

Frequently Asked Questions

Do I need to change my car’s stock expansion tank?
Race engines generate significantly more heat than typical road vehicles due to higher RPMs and prolonged strain. Performance expansion tanks are designed to withstand these higher pressure levels, preventing the tank from cracking or leaking under intense conditions. So, if you’re planning to race your MX-5 or chuck it around on a track day, we’d suggest upgrading the coolant expansion tank.

Do aftermarket expansion tanks prevent leaks?
Aftermarket expansion tanks for vehicles often come with reinforced connections and higher-quality fittings that minimise the risk of leaks. Leaking coolant during a race could cause overheating or even disqualification, so the more secure design of these tanks is a key benefit.

Should you upgrade all the cooling system components?

If you’ve upgraded other parts of your cooling system (like the radiator, fans, or hoses), getting an aftermarket coolant expansion tank can help ensure that all components are up to the task. A more efficient cooling system can help your engine run at its optimal temperature, especially under high-stress conditions.