Should the Air Conditioning Be Turned Off Before Shutting Down the Engine?

2 Answers
DiArya
07/24/25 2:17pm
It is essential to turn off the air conditioning first. Below is an introduction to car air conditioning: Car Air Conditioning Introduction: Car air conditioning consists of a compressor, condenser, throttle element, evaporator, fan, and necessary control components, forming an air conditioning system that regulates the temperature and humidity inside the vehicle, providing a comfortable environment for the driver. Working Principle: When the compressor operates, it inhales low-temperature and low-pressure gaseous refrigerant from the evaporator. After compression, the temperature and pressure of the refrigerant increase, and it is sent to the condenser. Inside the condenser, the high-temperature and high-pressure gaseous refrigerant transfers heat to the outside air passing through the condenser, causing it to liquefy and turn into a liquid. When the liquid refrigerant flows through the throttle device, its temperature and pressure decrease, and it enters the evaporator. Inside the evaporator, the low-temperature and low-pressure liquid refrigerant absorbs heat from the air inside the vehicle passing through the evaporator, causing it to evaporate and turn into a gas. The gas is then inhaled by the compressor for the next cycle.
Was this review help?
15
5
Share
ORonan
08/11/25 8:07am
As a veteran driver with over 20 years of experience, I always recommend turning off the air conditioning before shutting down the engine. The AC compressor relies on engine operation. If you don't turn it off before stopping the engine, the starter will have to handle the AC load during the next startup, which puts significant strain on the battery and may lead to difficult starts or premature battery failure. During hot summers when the AC is set to high, the starting pressure is even greater. I've seen many car owners neglect this and end up with drained batteries or damaged starting systems. Developing this simple habit can extend the life of both your starter and battery, making startups smoother. There's an added benefit - with reduced engine load, you might even save a tiny bit of fuel. I always turn off the AC before parking, and my long-running vehicle has fewer issues. Paying attention to these details is always better than spending big on repairs later.
Was this review help?
18
3
Share
Expand All
More Forum Discussions

What is the Function of a Car Air Filter?

The function of an air filter: It filters out particulate impurities in the air, ensuring that a sufficient amount of clean air enters the cylinders and preventing airborne dust from being sucked into the engine, which could accelerate wear on the piston group and cylinders. According to the car's maintenance manual, the air filter should generally be replaced every 10,000 to 20,000 kilometers or during every other maintenance interval. However, it is recommended to clean the air filter every 5,000 kilometers to reduce the buildup of throttle sludge. The location of the car's air filter is determined by the intake system and engine structure, usually found in the air cleaner on the engine's intake pipe. There are two types of air filters in cars: dry and wet. Dry filters are made of paper or organic materials, while wet filters are made of metal mesh. Air filter: It is a type of filter, also known as an air cartridge, air cleaner, or style filter. It is mainly used in engineering vehicles, cars, agricultural vehicles, laboratories, sterile operating rooms, and various precision operating rooms as an air filtration device. During operation, the engine draws in a large amount of air. If the air is not filtered, airborne dust can enter the cylinders, accelerating wear on the piston group and cylinders. Larger particles entering between the piston and cylinder can cause severe cylinder scoring, especially in dry and sandy working environments. The air cleaner is installed in front of the carburetor or intake pipe to filter out dust and sand particles from the air, ensuring that sufficient, clean air enters the cylinders. Dirty air cleaner: Using a dirty air cleaner while driving can restrict engine airflow, leading to incomplete fuel combustion, unstable engine operation, reduced power, and increased fuel consumption. Therefore, it is essential to keep the air cleaner clean. The car air cleaner is a device that removes particulate impurities from the air, consisting of one or several air filtration components. Its main function is to filter out harmful impurities from the air before it enters the cylinders, reducing early wear on the cylinders, pistons, piston rings, valves, and valve seats. Thus, air must pass through the fine filtration of the air cleaner before entering the cylinders. A dirty air cleaner can cause poor engine performance, excessive fuel consumption, and engine damage. When inspecting the air cleaner, if minimal dust and light clogging are found, it can be cleaned using high-pressure air blown from the inside out and reused. Excessively dirty air filters should be replaced promptly.
12
3
Share

What is the shelf life of engine oil after opening?

Engine oil has a shelf life of 6 to 9 months after opening. Engine oil is highly sensitive to moisture in the air, ambient temperature, and light exposure. If exposed to air for prolonged periods or under strong light, it typically becomes ineffective. Using engine oil past its shelf life can cause significant damage to the car's engine, such as poor lubrication and compromised cooling effects. Engine oil, also known as engine lubricant, is often referred to as the 'blood' of a car. It serves multiple functions including lubrication, cleaning, cooling, sealing, wear reduction, rust prevention, and corrosion protection. A simple method to check the shelf life of engine oil is to observe changes in its viscosity, assess whether the smell has faded, and check for any color changes.
6
1
Share

How Do Beginner Drivers Judge the Distance Between Cars?

Methods for beginner drivers to judge the distance between cars include: 1. Judging the left-side distance: You can use fixed reference points on the car to determine the distance. When the midpoint of the left rearview mirror aligns with the left boundary line, the distance between the car and the boundary line is 1.5 meters; 2. Judging the right-side distance: When the white line is at the halfway point of the right side of the engine hood, the distance between the car and the right boundary line is 30 centimeters. When the white line is at one-third of the right side of the engine hood, the distance is 60 centimeters; 3. Judging the position of the right front corner: When the car is 20 centimeters away from an obstacle, the lowest visible point of the obstacle is at 80 centimeters.
2
3
Share

What brand is Horizon?

Horizon is a tire brand under the American Horizon brand. It is a professional tire company registered in the United States, Qingdao Coast Tire Co., Ltd., primarily serving the American replacement tire market, providing services such as tire sales, warehousing, logistics distribution, American product design technical support, product development, and market information. Relevant information about tires is as follows: 1. Tires are circular elastic rubber products assembled on various vehicles or machinery to roll on the ground. They are usually mounted on metal rims, supporting the vehicle body, cushioning external impacts, achieving contact with the road surface, and ensuring the vehicle's driving performance. 2. Tires are often used under complex and harsh conditions. During driving, they endure various deformations, loads, forces, and high and low-temperature effects. Therefore, they must have high load-bearing performance, traction performance, and cushioning performance. At the same time, they are also required to have high wear resistance and flex resistance, as well as low rolling resistance and heat generation.
16
0
Share

How to Tell if the Car Body is Straight While Driving?

Methods to determine if the car body is straight while driving: You can use the central divider line or edge line of the road as a reference. When the vehicle is moving, if the markings visible in both side mirrors appear parallel to the car body, then the car body is aligned straight. Otherwise, minor adjustments are needed. For parking situations where no other cars are nearby, check through the rearview mirror whether the rear of the car is parallel to the road edge or parking lines. If there are adjacent vehicles, observe through the rearview mirror whether the distance to the neighboring car is equal at both front and rear - equal distances indicate proper alignment. If the rear of your car is too close to the adjacent vehicle or the front is too close to it, this indicates the car body is at an angle.
13
3
Share

What does 265/65r17 mean?

265/65r17 is the specification of a tire. 265 refers to the tire width of 265mm, 65 refers to the aspect ratio, meaning the section height is 65% of the width. R indicates that the tire is a radial tire, and 17 means the rim diameter is 17 inches. Tires with a high aspect ratio have longer sidewalls, providing better cushioning and relatively more comfort, but weaker resistance during turns. Conversely, tires with a low aspect ratio and large inner diameter have shorter sidewalls and wider treads, resulting in a larger contact area and the ability to withstand greater pressure. They are more sensitive to the road surface and offer greater lateral resistance during turns. The normal tire pressure for a car ranges between 230-250kpa. However, the specific normal tire pressure should be based on the manufacturer's recommended value, which can usually be found in the vehicle's user manual, on the label near the driver's side door (B-pillar), in the drawer next to the driver's seat, or on the fuel tank cap. Car owners should develop the habit of regularly checking tire pressure. If the tire pressure frequently exceeds 20% of the normal pressure, the tire's lifespan will decrease by 10%; if it frequently falls below 30% of the normal pressure, the tire's lifespan will be reduced by 52%.
2
1
Share
Cookie
Cookie Settings
© 2025 Servanan International Pte. Ltd.