Why do used cars consume more gas than they did originally?

This is a normal natural wear and tear process that will occur during vehicle operation.

Dirty engine air filter

According to the manufacturer's recommendation, the air filter replacement period ranges from 15,000 to 20,000 km. However, this also depends on operating conditions, such as in polluted places, it should be replaced earlier at the 10,000 km mark or in clean places it can be longer.

A dirty air filter will limit the amount of air entering the combustion chamber, leading to waste in the ignition process. If not checked and replaced periodically, the engine will be affected over time. This is also the main cause of fuel consumption or black smoke.

Low tire pressure

Tires that are too soft or not inflated enough will cause the engine to bear more load due to frictional resistance being greater than standard. Normally, popular car models in the Vietnamese market have an average tire pressure of 2.3 to 2.5 bar.

Car owners can ask garages and maintenance centers to inflate their tires according to this tire pressure. In addition, they can equip themselves with a tire pressure monitor mounted on their vehicle to monitor and identify which tires lose pressure during operation.

Degraded oil, lack of oil

Changing the oil is something that needs special attention and must be done periodically and regularly. Because oil is considered the most important fluid of the engine, it both lubricates and cools the engine. Over time, if the oil is not changed, the engine will deteriorate, overheat, and consume more fuel.

In addition to regular oil changes, users need to know the basic oil parameters suitable for the engine and distinguish between oil for diesel and gasoline engines. If the oil index is not changed correctly, it will greatly affect the operation process and this is also one of the factors that make the vehicle consume more fuel.

Spark plug wear

When operating about 40,000 to 60,000 km, users should check the vehicle's spark plugs to see how they are. With the above km mark, the spark plugs may be dirty and worn, which causes the ignition process to fail, leading to incomplete combustion of the fuel and air mixture or engine failure.

At this time, the engine ignition will not be at its most effective, forcing the engine to work harder, causing the car to consume more fuel. Worn and dirty spark plugs can also easily lead to many errors such as the car being difficult to start, the car stalling in the middle of the road, the car jerking when accelerating...

Lack of coolant

An equally important fluid in a car is the coolant. This fluid ensures that the engine operates at optimal performance at a certain temperature. However, when this fluid is depleted, it can lead to many unpredictable consequences.

Specifically, the amount of coolant leaking will cause the engine to overheat, forcing it to work harder to ensure performance. This leads to more fuel loss. If the coolant loss is too much, it can cause the vehicle to seize and not be able to continue operating.

In addition, when the temperature sensor is damaged, the ECU system will have signals that are incorrect compared to actual operating conditions, leading to excess or shortage of fuel injected, causing the vehicle to operate erratically. This can also lead to the vehicle consuming wasteful fuel.

Driving habits

In addition to the above factors, driving violently, accelerating and decelerating suddenly, braking continuously or overloading also causes the vehicle to consume more fuel than normal. Or not turning off necessary electrical equipment also leads to fuel burning.

In addition, some new drivers or women forget to release the handbrake, causing their cars to consume more gas than usual.