
Semi-synthetic engine oil is generally suitable for small naturally aspirated engine vehicles. The relevant explanations are as follows: Introduction: Semi-synthetic engine oil is a type of automotive engine oil that uses semi-synthetic base oil. Cars using semi-synthetic engine oil typically require an oil change every 7,500 kilometers, whereas conventional engine oil usually needs to be replaced every three months. Additional Notes: The frequency of oil changes should be determined based on actual driving conditions and habits. In more severe driving environments, earlier replacement may be necessary. Oil change intervals are not fixed and require the car owner to make a reasonable choice. The type of engine oil should also be selected with reference to the recommendations in the vehicle's maintenance manual.

I find that semi-synthetic oil is particularly suitable for daily commuter cars, especially those with naturally aspirated engines from Japanese and Korean brands. My colleague's Corolla, which has run 80,000 kilometers, has been using semi-synthetic oil all along, and it's perfectly adequate for city commuting. If you drive less than 10,000 kilometers a year or own an entry-level domestic car, using full synthetic oil is quite a waste. However, it's worth noting that older German cars may not be as compatible, as their enlarged engine clearances tend to burn oil. The most economical maintenance interval is to change the oil every 7,000 to 8,000 kilometers—more durable than mineral oil and about one-third cheaper than full synthetic.

After repairing cars for ten years, I've found that semi-synthetic oil is most suitable for affordable cars under five years old. It's particularly cost-effective for small-displacement naturally aspirated engines below 1.6L, like the Fit and Sylphy. I remember last year a Great Wall H6 owner insisted on switching to full synthetic, which was completely unnecessary since he only used it for city commuting. But for turbocharged (T) vehicles or those frequently driven on highways, I'd recommend going with full synthetic. Nowadays, domestic semi-synthetic technology is quite mature, with brands like Longpan and Kunlun offering SL-grade semi-synthetic oil for just over 100 yuan per barrel. A change at a roadside shop costs less than 300 yuan.

Semi-synthetic oil is actually a compromise. For someone like me driving an old Bora, where the engine has minor oil consumption, semi-synthetic is actually suitable. Using mineral oil for a new car seems stingy, while full synthetic is unnecessary. Especially for compact cars within three years, the manufacturer's maintenance manual usually permits the use of semi-synthetic oil. However, it's important to note that vehicles frequently carrying heavy loads or climbing slopes are not suitable, as the high-temperature shear value is insufficient. In northern winters, using 5W-30 semi-synthetic oil ensures very smooth starts, with much better low-temperature fluidity than mineral oil.


