This week on X, a video of a man opening up an overheating car’s cooling system is trending at a clipping pace. In the last 24 hours, it earned 15 million views. You can watch it below.
But first, a PSA: Never, ever open the radiator cap on a hot engine. The steam can cause debilitating burns. This X post is a solid case in point.
So not cool
In the clip, a man uses what looks like a bright microfiber towel to grip the cap on a steaming BMW’s coolant reservoir. For starters, the steam should immediately indicate to the giggling group of friends that the system is at an unsafe handling temperature.
Disregarding this condition, the guy untwists the cap until an immense, highly pressurized geyer blows.
The man obviously burned his hand, maybe more. Fortunately, he managed to dart away from the engine bay while steam and fluid spewed out of the reservoir.
Why is this interesting enough for 15 million people to watch?
While many folks have heard not to open the radiator cap right after your engine overheats, few have seen exactly why. An overheating engine builds incredible pressure. Opening the system under such pressure causes the rapid escape of heat, steam, and fluids. In a word, it’s super dangerous to anyone nearby.
Moreover, many viewers wonder what the heck that brown stuff is coming out of the reservoir. One commenter asked, “Why did he have Baked Beans in there?” Car people recognize the darkened coolant as “chocolate milk” or “milkshake.” This is a clear indication of oil mixing with coolant. The condition results from a severe breach between the two closed systems. In this case, I bet the cylinder head gasket or even the head itself warped from overheating, allowing the fluids to mix.
It’s a severe, costly mechanical malfunction that, at a minimum, requires cooling system repair and likely a cylinder head gasket replacement with head machining. At worst, engine repair or replacement is in order.
Please, wait until an overheating car cools off before tinkering with it.
