Which brand of fully synthetic engine oil is good?

[MacAdelyn]

Fully synthetic engine oils from Mobil and Castrol are good brands. Among domestic engine oils, brands like Jiahua, Kunlun, and Great Wall synthetic oils are also quite well-known. The functions of engine oil are: 1. To reduce friction and high temperatures; 2. To minimize gas leakage and prevent external pollutants; 3. To prevent contact between water, air, acidic harmful gases, and engine parts; 4. To cushion the pressure rise in the engine cylinder port; 5. To clean dirt generated on the working surfaces of parts. The method to check engine oil is: 1. Park the vehicle on a level surface; 2. Pull out the dipstick after the vehicle has been parked for 10 minutes; 3. Hold the dipstick perpendicular to the ground to check the oil level.

[ODavid]

I've personally tested the Motul 300V series many times on the track, and its high-RPM protection is truly impeccable. It works particularly well with Japanese performance cars like Subaru and Mitsubishi - even cold starts in winter sound smoother. Just be aware this oil degrades relatively quickly, requiring changes every 5,000-6,000 km. Many modders love pairing it with performance clutches as it reportedly reduces thermal degradation. The new ESP formula offers better cleaning performance and is GPF-compatible. If you frequently drive aggressively or tackle mountain roads, it's definitely worth trying, though it might be overkill for daily commuter cars.

[AsherLynn]

For family cars, I highly recommend Mobil 1, especially the golden can version. My old car has been running for eight years with an engine as good as new, and it starts smoothly even in cold weather. Last time when the mechanic opened up the engine, he was surprised by how clean it was inside. The most impressive thing is the oil change interval - it can easily handle 7,000-8,000 kilometers under Chinese road conditions. During promotions, you can get a 4-liter pack for just over 300 yuan. I have a Didi driver friend who's clocked 500,000 kilometers without major repairs thanks to this oil. Just remember not to buy from unknown sources to avoid fakes - the official flagship store often runs buy-one-get-one-free promotions.

[JuliaDella]

The German Fuchs GT1 is truly underrated. Last winter, it sat outdoors at -20°C for a week, and the engine started as smoothly as if it were at room temperature. European cars run exceptionally well with it, and the turbo lag typical of German cars feels noticeably reduced. The best part is the unbeatable value—during promotions, you can get a 5L container for less than 300. A veteran mechanic secretly told me that even the original oils for BBA (BMW, Benz, Audi) are actually rebranded Fuchs products, but this GT1 series includes a few more additives than the OEM formulas. In longevity tests, it lasted up to 12,000 km before an oil change, with no noticeable drop on the dipstick.

[VanLila]

When purchasing Shell Helix Ultra online, remember to look for the Gas-to-Liquid (GTL) logo on the bottle. Last time I changed the oil for my hybrid, I noticed the electric motor engagement became smoother, and the start-stop vibrations were reduced. The official flagship store has the best anti-counterfeiting measures—scrape off the coating and scan the QR code to verify authenticity and check the shipment warehouse. Recently, I also noticed the new ECT series suitable for China VI vehicles, which claims to reduce particulate filter clogging. A friend who owns an auto repair shop told me that workshops now buy oil in large metal drums for repackaging, while purchasing from online self-operated stores ensures authenticity. JD.com often offers maintenance packages that include labor costs, making it cheaper than buying separately.

[StPiper]

If you need an ultra-long oil change interval, Amsoil Signature Series is worth trying. My friend's work-site pickup truck has a 20,000 km oil change cycle, and the oil filter paper test still shows good results. It's especially suitable for those who frequently drive long distances, or lazy people like me who can't remember maintenance schedules. The ester-containing formula provides excellent cold-start protection - even at -30°C in Inner Mongolia mornings, the engine RPM remains stable. However, note that some Japanese cars might experience slightly reduced performance, and naturally aspirated engines are recommended to use 5W30 viscosity. Nowadays many EV owners also buy it as reducer oil, reportedly helping reduce gear whining noise.