You're cold. Your car is cold. Everything is cold. Wouldn't it be great to just get into your car when it's all warmed up? I mean, go straight from your warm house to your warm car and drive off... Eh, but alas! We can't because Mr. Internet said we can't. Or can we? ​ Youtube, random Google searches and your grandsons best friend will tell you that'll destroy your car. Fact is, somehow with all their internet experience, they are all wrong. Warming up your car a bit in the winter will not harm your car. Now, I said just a bit. More on this later. ​ If you want to read to this point and just trust me, go on then and thank you. But yes, warm up your car for about 5-10 minutes and then get in and drive it easy until it's fully warmed up and then drive normally. You'll enjoy a nice toasty car and go on about your day with little worry of the haters telling you to risk your life driving a frozen car because you can't see out of the windshield. If they still hate on your warm stop sign seeing self, just tell them Jeremy said it was ok. ​ Now, there are many schools of thought about why you shouldn't let your car idle in the morning but a big one is fuel consumption and another is wear and tear on the engine itself. I'm going to debunk these right now because honestly they are both ridiculous claims made by people that don't even know how engines work. ​ Basically, starting a car sucks in general. It's bad for the engine, it's bad for the environment, it's bad for your pocketbook and the idea of it makes me cry sometimes. What you're essentially asking of the engine when you turn that key or push the button is that you want it to rotate... The engine is basically just a pile of steel components that rub on each other a bit. While running there is usually a film of oil that separates these components to keep them from wearing. This oil is supplied by a pump that keeps oil pressure up enough to keep these metal parts suspended from each other. The engine rotates, the pump works, crucial components are lubricated and safe... Everything's good and a random goat in Ireland smiles. Now, when the car is cold, the oil is cold. And thick. It's like... . well, some adjective that describes something that doesn't flow well. This engine saving oil works much better when it's warm or what we in the industry call "optimum operating temperature". If we are discussing wear and tear, there's nothing more that'll wear your engine than asking a lot of it when it's not able to flow oil properly. But there is another side of this and it's my favorite part so hold on for the ride... Thermodynamics. One of my favorite words to say and one of my favorite fields of study in physics second only to Fluid Dynamics which will bore you to death so we'll save that for another post. Your engine is made of a lot of metal. Often different kinds of metal like iron and aluminum. These different metals have different thermodynamic properties, meaning they react to temperature changes at different rates. In my case here, we are talking about how heating an engine up is harmful so we'll focus on heat in general. If you take two different metals and try to heat them at the same time, you'll get two different expansion rates. Aluminum will expand at a different rate than steel or iron. In your engine, these aluminum and steel parts should be heated slowly to achieve temperature uniformly so they can expand together. This will help the engine as a whole work more efficiently because the tolerances remain constant. Differentiation during heat expansion causes many issues in engine development, I've spoken to many engineers about this and it's just true. Wish it weren't, it just is.. Gasket failure is most common because different metals rub together as they expand and contract. ​ So, we got oil flow (fluid dynamics, lol) and heat expansion. The story here is that you want your oil to heat up quick but not your engine itself. The only way to do this is to let it idle... ​ The computer that runs your engine has a program in it we call "cold start". What this does is makes your engine run at a high rpm for awhile when the engine is cold. It's doing this for a few reasons but the idea is, it wants to get warm quick with no load on it... meaning NOT DRIVING. It's literally revving itself up so it can get warm enough on its own. It doesn't need your help by driving to the coffee shop where you spend $9 for a coffee just to complain to the barista about $3 gas. Once the idle starts to come down then take off easy and be nice to it until it does come up to temperature. The idea is to not heat things too quickly so you can keep this heat expansion thing in check. As far as fuel consumption... Yes, it uses more fuel cold than it does warm. Heating it up quick uses less fuel and creates less emissions in the end but very little in the grand scheme of things. A cow farts and that essentially offsets an entire block of cold start issues... I mean, it's negligible. Just do it. Thank you for reading ​ -Jeremy