Should You Let Your Car Warm Up Before Driving?

Remember those cold mornings when you were a kid? Dad would go out, fire up the station wagon and come inside to drink coffee while the car warmed up. Warming up the car just makes sense, right? Actually, it does not.

There is an old saying that just because 50 million people say something, it doesn't make it true. This is very much the case with the notion of letting your car warm up. You've heard you are supposed to do it and, logically, it seems to make sense. The only problem, of course, is it is nonsense if your car is fuel injected, which most are these days.

First things first - your father was not wrong about warming up the old station wagon. Cars used to have carburetors to handle the fuel input into the engine. Carburetors were not precise instruments and they worked better when warmed up. By letting the car idle, the engine would warm up. Heat would rise and the carburetor would get nice and toasty.

Nearly all modern cars have ditched the carburetor approach. Now, they are designed to use electronic fuel injection systems controlled by computer programs and processing units. These new systems do not need to a warm up period. The programs work right off the bat. When the car is cold, the programs will adjust the fuel flow to come up with the most efficient engine performance solution. As the car warms up, the software program will continue to adjust the fuel mixture.

Ah, but what about lubrication? Letting the car warm up gets the oil moving around and so on, right? Again, we have to look at how the modern car works and the products that have been tailored to it. Modern oil does not come from the ground directly to your car. It is processed, refined and tweaked to create certain properties. One of them is a "stickiness" that causes the oil to bond at a molecular level with the engine parts. This means that there is effectively a layer of oil on the parts at all time, even before you start the car!

The desire to fire up your car and let it sit while warming up is one you really have to fight. All you are accomplishing when you do this is wasting gas and kicking out fumes from the tailpipe. Time is money. Get a move on!