When talking about an automotive cooling system, it’s easy to keep the focus on major components like the fan, radiator, water pump, and thermostat.

But don’t overlook the role of your humble radiator cap.

You radiator cap is often an unsung hero of your vehicle’s cooling setup, maintaining the proper pressure within the system and keeping excess coolant from bursting out of your radiator.

That’s why we were compelled to share this video from the cooling system experts over at MotoRad.

(Image/The MotoRad YouTube Channel)

MotoRad makes a wide range of thermostats, cooling system pressure testers, and—of course—radiator caps, so its techs know an awful lot about keeping your engine running at its optimal temperature.

And to prove it, they made this short video that’ll explain how a radiator cap works, how radiator cap design has evolved over the years, and why it’s really, really important to have the right cap for your radiator to ensure good cooling system performance.

Better still, they explain how pressure is so vital in your cooling system and why pressure testing is such a critical step in diagnosing an overheating issue.

So if you’ve never given much thought to your humble radiator cap—or if you’re constantly fighting an overheating engine—this video on radiator cap design from MotoRad is a good one to watch: