How often should the oxygen sensor be replaced?
2 Answers
There is actually no fixed replacement interval for automotive oxygen sensors, but it is recommended to replace them for vehicles with over 100,000 kilometers. Oxygen sensors are divided into upstream (front) and downstream (rear) sensors. Owners who purchase them themselves are advised to choose formal channels, as you get what you pay for. More relevant information is as follows: 1. There are usually two oxygen sensors. The one located in front of the three-way catalytic converter is called the upstream (front) sensor, while the downstream (rear) sensor is located behind it. The upstream sensor is used to adjust the mixture concentration, while the downstream sensor monitors the working condition of the three-way catalytic converter. Failure of the upstream sensor can prevent mixture correction, leading to increased fuel consumption, reduced power, and other phenomena. Failure of the downstream sensor means the operating condition of the three-way catalytic converter cannot be determined, and if the catalytic converter fails, timely maintenance cannot be performed. 2. Sensor poisoning is a common and difficult-to-prevent fault, especially in vehicles that frequently use leaded gasoline. If the lead poisoning is minor, cleaning can restore normal operation. However, if lead penetrates the interior, obstructing the diffusion of oxygen ions and rendering the oxygen sensor ineffective, replacement is the only option.
I've been modifying cars for ten years, and there's really no fixed replacement interval for oxygen sensors. Last year, my Focus failed the emissions test because the front oxygen sensor was dead after running 120,000 kilometers. For those who usually drive short distances in the city or frequently refuel at small gas stations, it's recommended to check the sensor every 80,000 to 100,000 kilometers. If you notice a sudden 20% increase in fuel consumption, slower cold starts, or black smoke from the exhaust pipe, chances are the sensor is reacting sluggishly. Don't push it—replacing it with an OEM part costs just over 600 yuan, and damaging the catalytic converter would be much more costly. The mechanic said using fuel additives regularly can extend the sensor's lifespan, and I've found it effective over the past six months.
