Should the engine oil be changed when the car is hot or cold?
3 Answers
You can change the engine oil whether the car is hot or cold, but relatively speaking, it is better to change the oil when the car is hot. After the car is hot, the viscosity of the oil becomes thinner, and the fluidity improves. Impurities and sludge will be discharged well with the waste oil and will not adhere to the inner surface and bottom of the engine casing. Relevant information about engine oil is as follows: 1. Introduction: Engine oil, also known as engine lubricant (English name: Engine-oil), has a density of about 0.91×10³ (kg/m³). It can lubricate and reduce wear, assist in cooling, seal and prevent leaks, prevent rust and corrosion, and provide shock absorption for the engine. It is known as the 'blood' of the car. 2. Composition: Engine oil consists of two parts: base oil and additives. The base oil is the main component of the lubricant, determining its basic properties. Additives can compensate for and improve the shortcomings of the base oil, giving it certain new properties, and are an important part of the lubricant.
It's better to change the oil when the engine is warm. As the oil temperature rises, its fluidity increases, making it easier for the old oil to drain from the bottom of the engine, ensuring a cleaner removal and avoiding residue that could affect the performance of the new oil. I usually drive for about 10 minutes to warm up the engine, then turn it off and wait 5-10 minutes for it to cool down to a warm state before starting the oil change. This method improves efficiency and ensures safety. Although changing oil when the engine is cold avoids the risk of burns, the oil's high viscosity makes it drain slowly and incompletely. After the change, remember to check that the new oil level is at the midpoint of the dipstick. It's recommended to change the oil regularly every 5,000 to 7,500 kilometers, along with replacing the oil filter to extend the engine's lifespan. In daily maintenance, changing the oil when the engine is warm saves time and effort, ensuring smooth engine operation.
I prefer changing the oil when the engine is warm. After driving a short distance, the oil heats up and flows faster, allowing the old oil to drain quickly once the drain plug is opened. I let it cool for a few minutes before starting to avoid burns or oil splashes. Changing oil when the engine is cold means the oil is too thick, often requiring a long wait, and there may be sludge residue, affecting the performance of the new oil. After the oil change, I start the engine and let it idle to check the oil level and for any leaks. I inspect the filter screen every six months to ensure it's not clogged. Long-term experience has taught me that changing oil when the engine is warm is more efficient and practical.
