Depends how hot and how cold. Generally engines are designed to run best with a certain range of temperatures that they would normally see when operating in normal conditions. Metals expand and contract with heat, oils and fuels and batteries operate differently at different temperatures.
For very cold starts batteries put out less power, oil is significantly thicker, compression in the engine is quite low.
Hot starts are much less of a problem because the engine is supposed to run while it’s hot, and nowhere in the world does the weather get hotter than an engine at operating temp. In extreme hot temps batteries can become damaged and fueling can be imprecise, but still less of a problem than extreme cold starts
Latest Answers