Why does fuel consumption increase after changing transmission oil?
2 Answers
The reasons for increased fuel consumption after changing transmission oil are as follows: Insufficient tire pressure and tire wear: Insufficient or low tire pressure increases friction between tires and the ground, resulting in greater resistance and higher fuel consumption; Severe tire wear often leads to slipping, which also increases fuel consumption; Poor fuel quality: Pay attention to fuel quality and regularly clean carbon deposits; Poor quality gasoline can increase carbon deposits, which roughens the intake pipe walls, affecting air intake efficiency and mixture quality, leading to a sharp rise in fuel consumption; Regularly check the oxygen sensor: This is a ceramic component located on the engine exhaust pipe, used to detect and control the oxygen-to-fuel ratio; After prolonged use, the electronic fuel injection system's computer can no longer obtain information about oxygen concentration in the exhaust pipe, often resulting in a higher concentration of the mixture in the engine and increased fuel consumption.
I've encountered many car owners experiencing increased fuel consumption after an oil change. There are three common reasons: First, the viscosity of the new transmission fluid is incorrect. For example, if the factory requires 75W-90 oil but 80W-90 is used instead, the increased viscosity will raise transmission resistance, forcing the engine to work harder and naturally consume more fuel. Second, the oil change quantity wasn't properly controlled. If one or two extra notches of oil are added, the internal hydraulic pressure increases, making the transmission work harder. Third, older vehicles need a break-in period after an oil change, as the computer needs to readjust to driving habits. Right after the change, the system is constantly adjusting shift logic, making fuel consumption fluctuations quite common. I recommend first checking the dipstick to see if the oil level is correct, then recalling whether the correct oil specification was used. If there's no improvement, it's best to have a repair shop check the matching status of the transmission control module.
