Diesel Engine Oil CI-4
40,000 km product positioning with two SAE grades and detailed detailed inspection evidence.
A premium heavy-duty diesel engine oil range in SAE 15W-40 and 20W-50, positioned for extended service up to 40,000 km only where the OEM, operating severity and oil analysis permit. This page combines measured viscosity, viscosity index, cold-cranking, HTHS, flash point, pour point, cleanliness and foaming data from the supplied 2026 CI-4 inspection reports with official API context for EGR-equipped diesel engines.
A measured-data story for dependable diesel lubrication
The following benefits are explained using the actual physical-property results in the supplied inspection reports—not invented performance percentages.
High-Temperature Oil-Film Strength
Measured HTHS viscosity is 4.36 mPa·s for 15W-40 and 4.81 mPa·s for 20W-50. These are 0.66 and 1.11 mPa·s above the stated 3.7 mPa·s minimum, supporting high-temperature oil-film retention under the reported test condition.
See HTHS data →Controlled Low-Temperature Cranking
CCS results are 6,200 mPa·s at -20°C for 15W-40 and 7,502 mPa·s at -15°C for 20W-50—respectively 800 and 1,998 mPa·s below their stated maximum limits.
Compare grades →Volatility & Temperature Margin
Open-cup flash points are measured at 248°C and 252°C—43°C and 37°C above the stated minima. Reported pour points are -32°C for 15W-40 and -27°C for 20W-50, each 7°C below its quality limit.
View temperature data →Cleanliness & Foam Control
Both reports record no water and no mechanical impurities. Reported foaming results are 0/0 for every listed test sequence.
Review quality checks →More than values: understand how each result sits against its report limit
These are transparent calculations derived from the supplied report values; they are not separate laboratory tests or universal performance guarantees.
For high-speed four-stroke diesel engines—including EGR applications—where CI-4 is specified
Use CI-4 only where the engine or equipment manufacturer permits the category, selected SAE grade, emissions hardware, fuel sulfur level and intended drain interval.
Heavy work. Clear grade selection.
Typical target equipment can include commercial vehicles, construction machinery, agricultural equipment and stationary diesel engines—subject to OEM approval.
Commercial Diesel Fleets
Trucks and buses with high-speed four-stroke diesel engines, including selected EGR-equipped fleets, whose manuals permit API CI-4 and the selected viscosity grade.
Construction Equipment
Suitable excavators, loaders, generators and site machinery operating under heavy loads.
Agricultural Machinery
Selected tractors, harvesters, pumps and farm engines where API CI-4 is specified by the manufacturer.
Stationary Diesel Engines
Industrial or standby equipment requiring the stated service category and viscosity.
Complete comparison of the supplied 15W-40 and 20W-50 reports
Values below are transcribed from the supplied Shengxiang product inspection reports. They represent the stated measured results and quality indices for those reports.
| Analysis item | 15W-40 index | 15W-40 result | 20W-50 index | 20W-50 result | Test method |
|---|---|---|---|---|---|
| Appearance | Transparent | Transparent | Transparent | Transparent | Visual inspection |
| Kinematic viscosity @ 100°C | 12.5–16.3 mm²/s | 15.10 mm²/s | 16.3–21.9 mm²/s | 19.60 mm²/s | GB/T 265 |
| Kinematic viscosity @ 40°C | Reported value | 110 mm²/s | Reported value | 153 mm²/s | GB/T 265 |
| Viscosity index | Reported value | 144 | Reported value | 147 | GB/T 2541 |
| Pour point | ≤ -25°C | -32°C | ≤ -20°C | -27°C | GB/T 3535 |
| Water content, volume fraction | None | None | None | None | GB/T 260 |
| Mechanical impurities, mass fraction | None | None | None | None | GB/T 511 |
| Flash point, open cup | ≥ 205°C | 248°C | ≥ 215°C | 252°C | GB/T 3536 |
| CCS low-temperature cranking | ≤ 7,000 mPa·s @ -20°C | 6,200 mPa·s | ≤ 9,500 mPa·s @ -15°C | 7,502 mPa·s | GB/T 6538 |
| HTHS viscosity @ 150°C, 10⁶ s⁻¹ | ≥ 3.7 mPa·s | 4.36 mPa·s | ≥ 3.7 mPa·s | 4.81 mPa·s | NB/SH/T 0703-2020 |
| Foaming tendency / stability | 24°C ≤10/0; 93.5°C ≤20/0 mL/mL | 0/0; 0/0 | 24°C ≤10/0; 93.5°C ≤20/0; after 24°C ≤10/0 mL/mL | 0/0; 0/0; 0/0 | GB/T 12579 |
| Determination | PASS | PASS | Inspection report | ||
Units and conditions are shown as stated or standardized from the supplied reports. Blank quality-index fields in the original reports are presented here as “Reported value.”
What each laboratory property tells the buyer
Kinematic Viscosity
Shows how readily the oil flows at 40°C and 100°C. The measured 20W-50 values are higher than the 15W-40 values, confirming the heavier operating-viscosity profile.
Viscosity Index
Indicates the rate of viscosity change with temperature. The reported VI is 144 for 15W-40 and 147 for 20W-50, indicating comparatively stable viscosity-temperature behavior in these report results.
Pour Point
A laboratory indication of low-temperature flow. The supplied reports show -32°C for 15W-40 and -27°C for 20W-50. Pour point is a low-flow laboratory indicator—not a guaranteed engine-start temperature.
Open-Cup Flash Point
The lowest reported test temperature at which vapour can ignite momentarily under the specified method. Results are 248°C and 252°C.
Cold Cranking Simulator
Represents apparent viscosity during low-temperature cranking. The grades are tested at different specified temperatures, so the two CCS numbers should not be compared as if measured under identical conditions.
High-Temperature High-Shear
Reflects viscosity under severe high-temperature and high-shear test conditions. Both results exceed the stated minimum of 3.7 mPa·s.
15W-40 or 20W-50: select by the OEM manual—not by guesswork
The inspection data show clear physical differences. Suitability still depends on the engine design, ambient-temperature chart, operating condition and manufacturer recommendation.
15W-40
Broader cold-grade designationThe lower winter grade and lower measured operating viscosity may suit equipment whose OEM viscosity chart specifies SAE 15W-40.
20W-50
Higher operating viscosityThe higher measured viscosity and HTHS may fit selected engines and warmer-duty recommendations only where SAE 20W-50 is explicitly permitted.
Inspection, handling and publication essentials
What the supplied reports confirm
Both documents identify Shengxiang (Shandong) Energy Technology Co., Ltd. and state a final determination of Pass.
- Measured KV100 values fall inside the stated grade ranges.
- Pour point, flash point, CCS and HTHS results meet the stated report limits.
- No water or mechanical impurities are reported.
- Foaming results are reported as 0/0 for all listed sequences.
Recommended document practice
Keep marketing statements aligned with the authorized product documents and the intended market.
- Use the latest authorized TDS for published typical properties and product claims.
- Use the applicable SDS for safety, first-aid, transport and disposal information.
- Protect containers from water, dust, extreme heat and cross-contamination; keep them sealed and clearly identified.
- Treat 40,000 km as conditional product positioning—not a universal guarantee. The supplied inspection reports are titled 50,000 km, but neither report defines the operating protocol needed to validate a universal drain interval. Confirm service life through the OEM schedule, duty severity, fuel quality and used-oil analysis.
Important questions before selecting CI-4 40,000 km
Can CI-4 be used in every diesel engine?
No. CI-4 targets high-speed four-stroke diesel engines of the EGR/2004-emissions generation. Engines with newer aftertreatment systems may require later low-ash categories. Use only the API category and SAE grade listed by the OEM.
Which grade is thicker at operating temperature?
In the supplied reports, 20W-50 has higher measured kinematic viscosity at 40°C and 100°C and higher HTHS viscosity. This does not mean it is automatically better; the correct grade is the one permitted by the OEM.
Does the -32°C / -27°C pour point mean the engine will start at those temperatures?
No. Pour point is a laboratory low-flow property. Starting performance depends more directly on the specified winter grade, CCS requirements, battery, fuel system and engine condition.
Can the CCS figures be compared directly?
Not as identical-condition results. The 15W-40 value is measured at -20°C, while the 20W-50 value is measured at -15°C. Each should be judged against its own stated limit.
Are these values guaranteed for every production batch?
The supplied documents present measured results for their stated inspection reports. Use the latest authorized TDS for published typical values and the relevant certificate of analysis or inspection report for a specific batch.
What is the relevance of EGR to API CI-4?
API states that CI-4 oils are formulated to sustain engine durability where exhaust gas recirculation is used. EGR can increase soot loading and thermal stress in the lubricant, so the correct category, viscosity and maintenance interval remain important.
Does this page claim CI-4 PLUS or an API license?
No. API notes that some CI-4 oils may qualify for CI-4 PLUS, but the supplied inspection reports do not show that designation or an API EOLCS license number. Verify any licensing claim in the official API directory before using API quality marks.
Does “40,000 km” guarantee the same drain interval in every vehicle?
No. The website uses 40,000 km positioning, while the two supplied reports are titled 50,000 km. Their physical-property results do not define a universal field-test protocol or guarantee either interval. Follow the OEM schedule; extend only with approved maintenance policy and trend-based used-oil analysis.
