When choosing automotive lubricants, SAE viscosity grade and API quality grade are the most critical evaluation criteria. By mastering the following key points, it is easy to avoid 90% of inferior oil products on the market:

1、 SAE viscosity grade: password for low temperature start and high temperature protection

1. Interpretation of numbering structure (e.g. 5W-30)

First half "5W": Low temperature fluidity (Winter)

The smaller the number, the stronger the low-temperature performance (commonly 0W/5W/10W)

0W: can still be pumped at -35 ℃ (suitable for Northeast/Xinjiang)

10W: -25 ℃ applicable (limited to Jiangnan region only)

The second half "30": 100 ℃ kinematic viscosity

Japanese and Korean brands commonly use 20/30 (fuel-efficient orientation)

German old car recommendation 40 (high viscosity protection)

2. Oil selection guidelines for different climates

minimum temperature

Recommended SAE front-end

Representative Region

>-15 ℃ 10W Guangdong/Fujian

-15~-25 ℃ 5W Jiangsu Zhejiang/Hubei

<-25 ℃ 0W Heilongjiang/Inner Mongolia

3. Differences in choosing between new and old cars

New car: prioritize selecting according to the manual (e.g. Honda 1.5T must use 0W-20)

Old cars over 10 years old: can increase viscosity by one level (original factory 5W-30 → switched to 5W-40)

2、 API Quality Level: Evolutionary Scale of Engine Technology

1. The higher the alphabetical order, the newer it is

Starting with S: Gasoline engine (latest SP>SN>SM...)

Starting with C: Diesel engine (latest CK-4>CJ-4...)

SP/GF-6A: New Standard for 2020, Addressing:

Low speed spark ignition (LSPI) for direct injection engines

Wear and tear during the start stop of hybrid cars

2. Key performance comparison

API level

abrasion resistance

cleaning ability

Applications

SN ★★★☆★★★★ Before 2015, it was listed as a National Fifth Automobile

SP ★★★★★☆★★★★★★★ National VI B with GPF model

3. Identify the certification mark accurately

The oil drum must be marked with the API certified "donut" logo (as shown in the figure below)

Be cautious of the phrase 'compliant with API standards' (not tested)

3、 Oil selection rules for special vehicle models

Turbocharged engine

Must choose SP grade oil with turbocharger protection certification (such as Volkswagen VW50400)

Hybrid/New Energy Vehicles

C5/C6 standard oil products with low ash content (≤ 0.8% ash content) are required

Track/high-performance car

Choose high-performance oil with HTHS ≥ 3.5mPa · s (such as Mobil ESP 5W-30)

4、 Avoiding pitfalls guide: 3 types of engine oils that absolutely cannot be bought

Ambiguous labeling (such as only writing "synthetic engine oil" without labeling SAE)

API level lower than manual requirements (SN oil for National VI vehicles may damage GPF)

Extremely low price (4L full synthetic oil<￥ 150 must have problems)