How often does the Fox valve oil seal change?

Fox valve oil seal is recommended to be replaced every two to three kilometers. Valve oil seal is one of the important parts of engine valve group, and its function is to prevent engine oil from entering the intake and exhaust pipes; Prevent oil loss; Prevent the leakage of mixed gas of gasoline and air and waste gas; It can also prevent the engine from burning oil. Take the Fox 202 1 sedan 1.5L manual jump variant as an example: its gearbox is 6-speed manual, the body structure is a 4-door 5-seat sedan, and the air intake form is natural inhalation. The length, width and height of cars are 4647mm, 18 10mm respectively, and the wheelbase is 1468 mm.