As the vacuum builds in the cooling system, the second function of the two-way check valve comes into play. At a predetermined vacuum, the radiator cap allows coolant to be sucked from the ...

Disconnect when the target PSI is reached. Replace the air valve cap, and you're finished. To deflate your tires, you can apply pressure to the little stem inside the tire's air valve to release air.

Here’s a case where tacky novelty can actually result in something that keeps you safe and also makes you look cool. The Flash Tire Wheel Valve Cap Lights pretty much sum up their function in ...