Thanks, Helen. I appreciate you helping me think about cold weather during a summer heat wave. I’d say you should plug your block heater in at 17 degrees, Helen. Why not?
One of the big benefits of a block heater is that it lets your engine warm up more quickly. That means it can provide heat to the passenger compartment sooner. And whether it’s 5 degrees or “feels like 5 degrees,” those are butt-chattering conditions, and most of us want heat as quickly as possible.
As far as your engine goes, the block heater, often indirectly, makes your oil warmer and less viscous. That helps the battery. Batteries have less power in cold weather, and if the oil flows more easily, it’s easier for the battery to push the moving parts of the engine through that oil and get the car started.
In terms of longer-term engine benefits, well, the faster your oil circulates in those first few seconds after you start the car, the better for the engine. That was probably truer 25 years ago. Nowadays, oils are so good that they’re already circulating quickly and protecting the engine’s parts, even in very cold weather. But the block heater probably does help.
Now, regarding wind chill: Unless you consider your vehicle a sentient being, Helen, you can ignore wind chill completely. Wind chill measures how the wind affects your skin. Because we humans use our skin to evaporate heat from our bodies and cool ourselves off, blowing cold wind on our skin makes us feel colder.
It’s not actually colder. As the forecast said, it’s 17 degrees. But your experience is that it feels colder. Fortunately, your car does not have skin. You cover it in Carnauba Wax, not Nivea Skin Creme. So, to your car, it’s still 17 degrees out.
But even if it’s “only” 17 degrees, why not get heat faster? If you’re worried about the cost of running the block heater all night, get a timer. Set the block heater to turn on a few hours before you typically start the car. Your engine will thank you a little. Your butt will nominate you for sainthood, Helen.
Have a question about cars? Write to Ray in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email by visiting the Car Talk website at www.cartalk.com.
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