Automotive Fluids Buying Guide: OE Matching & Brand Comparison

Engine Oil: Viscosity and Certifications

Choosing viscosity: 0W-20 / 5W-30 / 5W-40

The lower the number before W, the better the cold flow (0W or 5W for cold winters); the number after W is the high-temperature viscosity. The owner's manual rules: (1) most new Japanese/Korean cars use 0W-20; (2) German/American cars typically 5W-30 or 5W-40; (3) turbocharged or heavy-duty use 5W-40. KUAINA full synthetic oil distributed by Biyang covers 0W-20 through 5W-40.

Full synthetic vs semi-synthetic vs mineral

Full synthetic: best performance and longest life (10,000-12,000 km), suits all cars. Semi-synthetic: balanced value, 7,500-9,000 km. Mineral: 5,000-7,500 km, for older cars or tight budgets. For family cars Biyang recommends full synthetic — longer change intervals plus less engine wear actually cost less over time.

Reading API / ACEA ratings

API is the US standard (SN/SN+ currently the highest gasoline rating); ACEA is the European standard (A3/B3/B4 for high-performance gasoline engines). Check the container label and make sure the API grade meets or exceeds the manufacturer's minimum.

Coolant: Boiling Point, Freezing Point and Chemistry

Ethylene glycol vs OAT (organic acid technology)

Conventional glycol coolant: change every 2 years / 40,000 km. Long-life OAT coolant (e.g. CHAMPION): 5 years / 250,000 km. Important: never mix conventional and OAT formulations. Biyang distributes CHAMPION coolant across all chemistries and can match one to your vehicle.

Choosing the freezing point: 10°C below your coldest temperature

-35°C or -45°C for far-northern regions; -25°C for temperate zones; -15°C for southern climates. The freezing point printed on the bottle is the minimum protection temperature.

Brake Fluid and Transmission Oil

Brake fluid grades and replacement

DOT4 is the mainstream for family cars (230°C boiling point); DOT5.1 for high-performance cars (260°C). Replace every 2 years or 40,000 km regardless of mileage — brake fluid absorbs moisture.

AT / CVT / DCT fluids must never be mixed

Automatic transmissions use ATF (e.g. Dexron VI); CVTs use dedicated CVT fluid; dual-clutch (DCT) gearboxes use DCT-specific fluid. Mixing them can destroy the gearbox. Biyang tech support can confirm your transmission type.

FAQs about Fluids & Lubricants

Answers compiled from years of hands-on experience by the Biyang technical team, to help you resolve sourcing and usage questions fast.

QIs full synthetic always better than semi-synthetic?▾

AIn performance, yes (oxidation stability, flow, anti-wear), but it must match the vehicle. Cars under 5 years old: full synthetic. Older engines with worn seals may prefer a slightly thicker semi-synthetic such as 5W-40.

QCan 0W-20 and 5W-30 be mixed?▾

AIn an emergency, topping up is acceptable, but long-term mixing is not recommended. Flush and refill with a single spec as soon as possible. Biyang recommends fixing one viscosity per vehicle.

QCan I keep using coolant that has changed color?▾

ANo. Cloudiness, discoloration or sediment means the coolant has degraded and must be replaced. Standard coolant every 40,000-60,000 km; long-life OAT every 100,000 km.

QHow often should transmission oil be changed?▾

AAT: 60,000-80,000 km. CVT: 50,000-60,000 km. Dry DCT: 40,000-60,000 km. Manual gear oil: 80,000-100,000 km or per the manual's lifetime-fill claim.

QIs KUAINA oil a Chinese brand?▾

AKUAINA is a Singapore-based lubricant brand well known across Asia-Pacific. Biyang is KUAINA's official distributor in China; its full synthetic oils are exported to 30+ countries in Europe and the Americas.

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