Is it worth warming up the engine in winter

The eternal theme of the need to warm up the engine in winter. There are probably more opinions on this than just stars in the sky. True, this topic is usually talked about by people far from the development and improvement of automobile engines. But what does the person who creates and optimizes racing engines at the American company ECR Engines think? His name is Dr. Andy Randolph and he designs engines for the NASCAR series.

The engineer notes that a cold engine suffers from two factors. First, at very low temperatures, the viscosity of the engine oil increases. Oil manufacturers partially solve this problem, roughly speaking, by mixing components with different viscosity characteristics: one with a low viscosity index, and the other with a high viscosity index. Thus, an oil is obtained that does not lose its properties at low or high temperatures. However, this does not mean that the viscosity of the oil does not increase with decreasing temperature.

In cold weather, the oil in the lubrication system thickens, and its movement along the oil lines becomes difficult. Especially if the engine has a high mileage. This results in insufficient lubrication of some moving parts until the engine block and the oil itself get hot. In addition, the oil pump can even go into cavitation mode when it starts sucking in air (this happens when the pumping rate of oil from the pump becomes higher than the suction line capacity).

The second problem, according to Dr. Randolph, is the aluminum that most modern engines are made of. The thermal expansion coefficient of aluminum is much higher than that of cast iron. This means that when heated and cooled, aluminum expands and contracts much more than cast iron. The main problem in this case is that the engine block is made of aluminum and the crankshaft is made of steel. It happens that in cold weather the block compresses much more than the crankshaft, and the shaft bearing sits tighter than it should. Roughly speaking, the "compression" of the entire engine and the reduction of clearances leads to increased friction of the moving parts of the engine against each other. The situation is exacerbated by the viscous oil, which cannot provide adequate lubrication.

Dr. Randolph definitely advises to warm up the engine a few minutes before starting. But this is just a theory. But how much does the engine wear out if the average driver starts the car every winter every day as soon as he starts it? But what about the opinion of respected experts who claim that prolonged engine warm-up only harms it?

In fact, there is no need to stand idle for 10-15 minutes, the oil takes a maximum of 3-5 minutes to reach the operating temperature range, depending on the brand of the oil itself. If it is minus 20 degrees outside, you will have to wait 5 minutes - so much oil needs to heat up to 20 degrees, which is enough for the necessary engine lubrication.