Why Should Warm Your Cold Engine

Recently, while I was ironing my dress shirts to an ideal crispness, the Midday news decided to play a story dealing with car myths. One of the myths that were featured was that of warming engines in the cold. A particularly husky man (kinda looked like a Chuck) who said he was an automotive technician stated that allowing your car to warm up in the cold is basically a waste of time in this day and age. He said that cars that are younger than 19 years of age do not need to be warmed up, you can simply head out after about a minute after starting.

 

To be quite honest, I was already in a bad mood as I had lost one of the plastic sticks that kept my dress shirt collars erect. Chuck’s comments, which I felt were a little ignorant, pushed me into a fit of rage. So I immediately stopped ironing my lopsided collar, put on some pants, and well here I am now.

Heating your engine during cold weather is necessary for many reasons, but I’m going to point out the three most easily understood concepts. So let’s start with the basics. Engines are made out of metal, usually steel or aluminum. When metal is cooled down, it shrinks slightly. If you need an everyday example, think of a jar that is stuck. If you run it under hot water for a few minutes, the jar will be easier to open because the lid will have expanded slightly. Engines have a lot of moving metal parts, many of which are in near contact with other pieces of metal. When an engine is cold, these parts are a little closer together, meaning that there is more resistance to motion.

Definitely would want to let this warm up...

Definitely would want to let this warm up...

Now, consider the following too; oil gets thicker as it cools down. Most of the fluids that live under your cars hood are oil based. If your cars been out in the cold, those oils will thicken up. And finally, metal gets brittle as cools.

...and this one...

...and this one...

So, lets do a quick recap. Because of the cold, the engine components will compress slightly, the necessary fluids (like the motor oil) will be less viscous, and the metal constructing the components itself will be more brittle than if they were warm . Consider that an engines crankshaft moves at a little less than a 1000 revolutions per minute at idle and it’s pretty easy to see that there are quite a lot of forces at work. Get moving and the revs will be jumping up and down. Unnecessary wear to the engine and its components will occur if you run a cold engine straight off the bat. You increase the chances of a shaft breaking, a piston wearing out, or even cracking the block.

...and this one...

...and this one...

Now, automakers are smart. They limit the redline of the engines when they are cold, increasing them as heat is retained (BMWs and Audis). That way, the engine has expanded completely, the fluids are nice and runny, and the metal is able to cope with the forces.  Also know that cold engines burn more fuel, and thus are less efficient.

Basically, if someone says warming your engine is stupid because new cars are sophisticated, ignore them and warm your engines.