How often should fully synthetic oil be changed?

[Dora]

Fully synthetic oil should be changed approximately once a year or every 10,000 kilometers, but the specific interval depends on the vehicle's driving conditions. If the car is primarily driven in urban areas with frequent idling, the oil change interval should be shortened. Fully synthetic oil is artificially manufactured by synthesizing various substances. Compared to conventional oil, fully synthetic oil has a longer change interval, extends engine lifespan, and helps clean the engine's cylinder walls. Synthetic oils are mainly divided into fully synthetic and semi-synthetic oils. The key difference between them is that fully synthetic oil can operate effectively over a wider temperature range and has a longer service life. For the same oil film requirements, fully synthetic oil can achieve the desired performance with lower viscosity, whereas semi-synthetic oil requires higher viscosity to meet the same standards. Car owners can refer to the manufacturer's maintenance manual for oil change intervals. If the fully synthetic oil chosen is of higher quality than the manufacturer-recommended oil, the owner may appropriately extend the service interval beyond the recommended period.

[IsabelFitz]

I've been driving my car for over a decade, and fully synthetic oil usually only needs to be changed every 10,000 kilometers or once a year. Last time during maintenance at the 4S shop, the mechanic mentioned that fully synthetic oil has exceptional durability and can easily last 3,000 kilometers more than semi-synthetic oil. However, since I mostly drive in congested urban areas where oil consumption is faster, I make it a habit to get it checked every eight or nine months. Once, I forgot to change the oil during a business trip and delayed it until 14,000 kilometers—the engine started sounding rough and dry, which scared me into changing it immediately. Remember two things: don’t just focus on mileage; change it when the time comes, and if you drive aggressively, it’s safer to change it a thousand kilometers earlier. With the environment being so harsh these days, the cleaning function of engine oil is even more crucial—don’t delay when it’s time for a change.

[SanEmerson]

Having worked in auto repair for over a decade, I've seen many engines requiring major overhauls due to oil-related issues. While fully synthetic oil can theoretically last 12,000 km, the reality depends on usage conditions. In stop-and-go city driving, the oil starts turning black and thinning after about 8,000 km. For frequent highway driving, it can easily go 15,000 km. Here's a pro tip: check your dipstick monthly - healthy oil resembles dark honey; if it's blackened or carbonized, change it early. Never cheap out on counterfeit oil - quality lubricants protect turbos and variable valve systems. Remember to replace the oil filter simultaneously, otherwise it's all for nothing.

[VanEdward]

The lifespan of full synthetic oil largely depends on operating conditions. For daily short-distance commuting with frequent cold starts, it's recommended to change every 8,000 km. For predominantly long-distance highway driving, this can be extended to 12,000 km. My vehicle frequently goes off-road, and when driving through muddy waters, I shorten the interval to 7,000 km. Oil temperatures exceeding 120 degrees Celsius accelerate degradation, so modified cars should pay attention to cooling. Turbocharged models require even more frequent changes—I've seen cases where turbo bearings seized due to oil degradation. Although newer long-life oils claim up to 20,000 km, it's advisable to be conservative.