The subject of whether or not to warm your car up in very cold weather has proven to be a far more contentious subject than I’d ever have imagined. Because of my radical warm-it-up-for-a-minute-or-so views, I’m no longer invited to some family holidays. But that’s okay, because finally someone has pointed a thermal camera at an engine so we can see what the hell is going on.

The video is from Engineering Explained’s very informative YouTube channel, and here they’ve pointed a camera at the flat-four in a 2016 Subaru that’s been sitting out all night in 22 degree (F) temperatures. It’s a pretty good typical winter morning for many people, so this makes for a good test.

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The thermal camera lets you see just how the engine (and the oil) heats up, and how the heat spreads throughout the engine. The engineer is waiting to see when the ECU decides the engine is warm enough to drop the RPM down from around 1800 to the usual idle speed of around 850 RPM.

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Yes, modern cars are much, much better at getting started in the cold, but even so the engineer here still suggests taking it easy on the engine while it’s cold, whether or not you wait at all. I’m still in the let the poor car at least warm up for a little bit—30 seconds to a minute or so—camp, and I find this video just makes me more secure in that.

Regardless, it’s a fascinating and colorful thing to watch.