
At 40,000 kilometers, the maintenance items for a car include changing the engine oil and oil filter, as well as replacing the air filter, cabin air filter, and fuel filter. Additionally, it is necessary to check various fluids, the battery, brake pads, and tires. The specific maintenance details are as follows: Air filter and cabin air filter: Check whether they need to be replaced. If they are not severely dirty, cleaning them may allow continued use. If they are heavily soiled, they must be replaced promptly. Fuel filter: Many car models require the fuel filter to be replaced at 40,000 kilometers. Key fluid checks: Fluids such as coolant, brake fluid, and transmission fluid generally need to be replaced. Battery: For most car models, the battery should be replaced promptly when the vehicle reaches 40,000 kilometers. Check brake pads and tires: Under normal circumstances, these do not need to be replaced at 40,000 kilometers, but if any abnormalities are detected, they should be replaced immediately.

My car just hit the 40,000-kilometer mark last year, and I specifically researched the maintenance checklist. The 40,000 km service is a mid-term maintenance milestone. At that time, changing the engine oil, oil filter, cabin air filter, and engine air filter was essential – especially in areas with poor air quality where filters need more frequent replacement. Brake fluid must be tested for water content; if it exceeds 3%, replacement is mandatory as it directly affects braking safety. Spark plugs should be replaced at 40,000 km if they're nickel alloy, otherwise poor ignition will increase fuel consumption. A wheel alignment and tire balancing are strongly recommended to prevent uneven tire wear. The dealership also recommended changing the coolant, but this can be postponed if the freezing point test meets standards. Finally, don't overlook basic inspections like all vehicle lights, chassis bolts, and tire wear – these will give your beloved car a second lease on life.

Both of our family cars have undergone 40,000-kilometer maintenance, and we've noticed some easily overlooked items. According to the manual, transmission fluid should be replaced for the first time at this mileage on certain models, especially for vehicles frequently stuck in traffic. The fuel filter hidden in the fuel tank must be replaced at 40,000 km, otherwise fuel line blockage could become problematic. Brake pad thickness requires special attention - replacement is recommended if remaining thickness is less than 5mm. Don't forget tire rotation, as drive wheels wear faster; swapping front and rear tires extends their lifespan. Have the battery health checked - replace it early if severely depleted. One winter it left me stranded halfway, which was a real lesson. After completing these maintenance items, the vehicle's condition can be restored to nearly 90% like new.

Last month, I just helped my cousin with his 40,000-kilometer maintenance. Here’s the most streamlined approach summarized in three parts: Basic maintenance is a must—change the engine oil and three filters on time, as old oil harms the engine. Don’t skimp on critical safety items—check brake pad thickness, test brake fluid moisture content, and inspect tire tread depth, as these directly affect emergency braking distance. Preventive maintenance offers the best value—inspect chassis rubber bushings for cracks and replace spark plugs to avoid stalling. Additional items depend on the car’s condition: check coolant for frequent long-distance driving and transmission fluid for frequent stop-and-go traffic. Stick to the manual’s key items—over-maintenance isn’t worth it.


