What is a Cold Start for Cars?
2 Answers
Car cold start refers to starting the engine when the coolant temperature is low, typically after the vehicle hasn't been operated for an extended period (such as overnight parking). After the engine has been shut off for some time, it cools down to temperatures significantly below normal operating levels, and engine oil largely drains back to the oil pan. Restarting under these conditions constitutes a cold start. Approximately 80% of engine wear occurs during cold starts. Therefore, it's crucial to pay attention to preheating (warming up) the engine before driving. Before warming up, component clearances are larger, and lubricating oil settles in the oil pan. The engine requires a period of warm-up operation for components to expand to their proper clearances. Simultaneously, the oil pump begins circulating oil to all necessary lubrication points.
Imagine the scene of starting your beloved car on a winter morning—inserting the key and turning it is what we call a cold start. It refers to igniting the engine when the oil is completely cold. At this point, no lubricating oil film has formed inside the engine, and the dry friction between the piston rings and cylinder walls is particularly damaging to the car. When I first started driving, I was always in a hurry to leave during winter, but later a mechanic reminded me that if the engine sounds rough during a cold start, it’s a warning sign. Let the car idle for half a minute to allow the oil pump to circulate the thick oil to all the bearings before setting off. Once the temperature gauge needle starts moving, you can gently accelerate to start. Friends in northern regions should pay extra attention—at minus twenty degrees Celsius, the oil can become as thick as honey. Forcing the car to move will produce painful metal grinding sounds. Make it a habit to wait three to five minutes until the tachometer stabilizes before driving. This can extend the engine’s lifespan by five years.
