3psi one way check valves

Product Description

Running an open system without pressure and losing coolant?

Well slip this in the 5/16" overflow tube and voilà; you have mild pressure to keep the fluid in your system. 

In an non pressure system the fluid evacuates due to:

excess coolant

thermal expansion 

excessive flow from higher speeds 

blocked and clogged tubes 

water pump impeller design flaws

This handy dandy little check valve will not suck back but it is a great tool for keeping the fluid in for longer.