Does an Automatic Transmission Car Need to Warm Up?

[StSophie]

An automatic transmission car does need to warm up. Generally, warming up should not exceed 2 minutes (within 30 seconds after starting, sufficient oil pressure has already been established inside the engine, and the oil can circulate smoothly). After a car has been parked for a long time, the engine oil flows back into the oil pan at the bottom of the engine. Therefore, when starting the engine after a prolonged period of inactivity (such as overnight), the upper part of the engine is initially without oil and lacks lubrication. It takes about 10 seconds after starting for the oil pump to circulate oil to the parts of the engine that need lubrication the most, such as the pistons, connecting rods, and crankshaft. However, even if you start driving immediately after starting the engine, as long as you avoid pressing the accelerator hard and maintain low-speed operation, the effect is the same as idling. Before the engine reaches its optimal operating temperature (approximately between 90-110 degrees Celsius), the fuel system, due to the still-low temperature, cannot effectively vaporize the gasoline completely. When the gasoline is not vaporized and remains in a wet, liquid state, it is difficult to ignite and start the engine. At this point, the choke valve comes into play, restricting some air from entering the cylinders to increase the gasoline/air mixture ratio and raise the engine speed to prevent stalling. Once the engine reaches its normal operating temperature, the automatic choke valve will naturally return to its normal state due to mechanical action. For cars with a manual choke valve, it is essential to remember to release the choke valve; otherwise, an overly rich fuel/air mixture will not only waste gasoline and reduce power but also cause incomplete combustion, resulting in black smoke. A cold engine typically takes between 7-8 minutes to over 10 minutes to reach its normal operating temperature, depending on the vehicle model. During this period, there is no need to warm up the car while stationary; simply avoiding high-speed driving is sufficient.