Is it necessary to warm up the engine in winter?

When winter arrives and temperatures are very low, the routine of warming up the engine before hitting the road begins. Because of the cold weather, it's tempting to let it idle until it warms up sufficiently.

But, letting a cold engine idle for a few minutes can damage it.

The engine is designed to operate properly at operating temperature, i.e., around 100°C (this may vary depending on the engine type). This means that, when cold, it has not yet expanded sufficiently, the gaskets cannot guarantee complete tightness, and internal tolerances are inadequate. If we accelerate sharply during this period, we create excessive pressure that can damage internal components or cause oil leaks.

Cold engines use more gasoline

When the engine is below its operating temperature, the gasoline doesn't vaporize properly, and some of it reaches the combustion chamber in the form of droplets, hampering combustion. To compensate for this, we pull the carburetor's choke cable to allow more gasoline in than usual (in engines with electronic fuel injection, this is done automatically, prolonging the injection time). In other words, the engine receives extra gasoline—the gasoline it really needs, plus the gasoline we know it won't be able to use because it won't vaporize due to the cold.

This excess gasoline that isn't burned remains on the cylinder walls, dissolving the layer of oil that protects it from friction with the piston and its rings. If we do this routinely, we can damage the interior of the cylinder and also the piston. At the same time, the oil becomes contaminated with gasoline, losing its protective properties.

To warm up the engine, drive... gently

To minimize this occurrence as much as possible, it's best to drive smoothly, avoiding sudden acceleration and high RPMs. This way, the engine will warm up more quickly and we'll avoid prolonged use of the choke. At the same time, the oil pressure will be higher than at idle.

Conclusion

To warm up the engine in cold weather, it's best to let it idle only as long as necessary and run smoothly until it reaches operating temperature. It's also essential to use a good synthetic oil to improve protection during start-up and the warm-up phase.