Is it necessary to replace all three filters when changing engine oil?
3 Answers
It is not mandatory to replace all three filters when changing engine oil. Below are the instructions for replacing the oil filter: 1. Relationship between the oil filter and engine oil: Generally, the oil filter is replaced simultaneously with the engine oil. If the oil filter is not replaced, dirt from the old filter may enter the engine, contaminating the newly replaced oil. Additionally, a heavily soiled oil filter will have reduced filtration efficiency, affecting oil pressure and potentially causing insufficient lubrication in the engine. 2. Replacement cycle for the fuel filter: The typical replacement interval for the fuel filter is 10,000-20,000 kilometers, and the same applies to the air filter. However, the actual replacement cycle should be determined based on specific conditions. For instance, the air filter cleans the air entering the engine by removing impurities. If these impurities enter the cylinders, they can cause abnormal wear and shorten the engine's lifespan. If the driving environment is harsh with poor air quality, the air filter should be replaced earlier.
I've been driving for over a decade, and every time I go to the repair shop for an oil change, the technician always asks if I want to replace the three filters. Actually, it's not necessary to replace all of them every time. The oil filter must be changed because new oil will mix with impurities from the old oil, affecting lubrication. As for the air filter, it depends on your driving environment. For example, if you often drive in dusty areas, you might need to replace it earlier, but normally changing it every 20,000 kilometers is sufficient. The cabin air filter mainly filters the air inside the car. If it's dirty, you might notice reduced airflow or odors, but it's not as critical as the oil filter. Usually, an annual inspection is enough. Personally, I prefer to only replace the oil filter and oil, while deciding on the air filter and cabin air filter based on how dirty they are. This saves money and reduces resource waste. The key is to check the vehicle manual or consult knowledgeable friends to avoid being upsold by the shop.
As a novice who just learned to drive, I was always confused when hearing about 'changing the three filters.' Later, I gradually figured it out: when changing the engine oil, the oil filter must be replaced with a new one. Otherwise, the dirt in the old filter will contaminate the new oil, leading to engine wear. However, the air filter and cabin air filter don't need to be replaced as urgently. They aren't changed as frequently as the oil filter. A dirty air filter can affect the engine's air intake efficiency, potentially increasing fuel consumption, while the cabin air filter is related to the freshness of the air inside the car. I learned to check them myself—using a flashlight to inspect dust buildup. If they aren't too dirty, I just clean them instead of replacing them. The technician told me that for normal driving, checking the air filter every six months is sufficient, so there's no need to spend extra money every time. Pretty practical advice!
