Which API standards address the LSPI issue?

API SN Plus and API SP both require LSPI testing. The latest API SQ (ILSAC GF-7) further strengthens LSPI protection, timing chain wear resistance, and fuel economy, while limiting sulfated ash to protect GPF systems.

What is the difference between OEM approvals and API certifications?

OEM approvals (e.g., MB 229.5) usually set higher specific standards for HTHS, TBN, and Noack, but older ones like 229.5 don't include LSPI tests. API SP/SQ focuses on LSPI protection. Ideally, an oil should carry both to provide maximum wear protection and LSPI mitigation.

How can I tell if an oil actually has an OEM approval?

Look for the terms 'Approvals' or 'Freigaben' (German). Avoid oils labeled as 'Performance Level', 'OEM Performances', 'Recommendations', or 'Suitable for', as these usually haven't undergone official factory testing.

When comparing oils with the same approval, which parameters matter?

Compare Flash Point (higher is better), 100°C Viscosity (lower is generally better within the same grade), 40°C Viscosity (lower is better for cold starts), Noack (lower is better, ideally <10), HTHS (higher for high RPM stability, >2.9 preferred), and TBN (higher is better for durability, >8 preferred).

How does 'Calcium' in oil affect the engine?

Calcium acts as a detergent but is known to trigger LSPI. API SP/SQ-certified oils limit calcium to under 2000ppm, often replacing some calcium with magnesium for cleaning.

W205 Oil Journey (4) - Understanding Engine Oil Parameters

Primary Certifications

API Certification

SN Plus / SP: Requires mandatory LSPI (Low-Speed Pre-Ignition) testing.
SQ (ILSAC GF-7): The 2025 standard, enhancing LSPI protection, timing chain wear resistance, and fuel economy. It limits sulfated ash to ≤0.9% to protect Gasoline Particulate Filters (GPF).

OEM Approvals (Manufacturer Specific)

Approval	HTHS	TBN	Noack (Volatility)
API SP / SQ	>2.6	N/A	N/A
ACEA A3 / B4	>3.5	>10	<13
ACEA A5 / B5	2.9–3.5	>8	<13
ACEA C3	>3.5	>6	<13
MB 229.5	>3.5	>10	<10
MB 229.51 / .52	>3.5	>6	<10
VW 502 / 505	>3.7	>7	-
VW 504 / 507	>3.5	>6	<11
BMW LL-01	>3.5	>10	-

Certification Overlap

MB 229.5: High wear protection standards, but lacks specific LSPI testing.
API SP / SQ: Lower wear standards compared to MB, but includes crucial LSPI protection.
Combined (229.5 + API SP/SQ) → Excellent wear protection + LSPI mitigation.
Visual Reference: Use the Lubrizol Relative Performance Tool to compare standards.

Marketing Word Games

Genuine Approvals (Officially Tested):

Approvals
Freigaben (German for Approvals)

Claims (NOT Officially Tested - Use with Caution):

Performance Level
OEM Performances
Recommendations
OEM Compatibility
Suitable for

Metrics for Comparing Oils with the Same Approval

Flash Point: The temperature at which oil vapors ignite. Higher is better for stability.
100°C Viscosity: Within the same grade (e.g., 5W30), a lower value often indicates better efficiency.
40°C Viscosity: Lower is better for reducing engine wear during cold starts.
Noack Volatility: Evaporation rate. Lower is better; look for values below 10%.
HTHS (High-Temp High-Shear): Measures oil film strength under stress. Higher is better for high RPMs; >2.9 is recommended for modern engines.
TBN (Total Base Number): Measures acid-neutralizing capability. Higher is better for durability; >8 is ideal.
Pour Point: The lowest temperature at which oil flows. A point below -50°C often indicates high PAO content.
VI (Viscosity Index): Indicates viscosity stability across temperatures (less critical than other metrics).

Base Oil Categories

Esters: Top-tier, excellent lubrication, but degrades quickly. Look for IR peak 1710 > 2.
Alkyl Naphthalenes (ANs): Premium and rare. Used to replace esters in PAO blends for better additive solubility. IR peak 740–890.
PAO (Polyalphaolefin): Top-tier synthetic. Usually blended with a small amount of esters for additive solubility. IR peak 720 > 1.
GTL (Gas-to-Liquid): Premium base oil converted from natural gas via Fischer-Tropsch synthesis. Performance is close to PAO. IR peak 720 ≤ 1.
VHVI (Very High Viscosity Index): Hydrocracked mineral oil. Highly purified, but still a Group III base oil.

Additive Components

Calcium (Ca): Detergent, but triggers LSPI. SP/SQ oils limit this to < 2000ppm.
Magnesium (Mg): Detergent that replaces some calcium to prevent LSPI.
Molybdenum (Mo): Anti-wear / friction modifier.
Phosphorus (P): Anti-wear.
Zinc (Zn): Anti-wear, typically found as ZDDP.
Boron (B) / Tungsten (W) / Titanium (Ti): Advanced anti-wear agents.

Recommended Brands

For Daily Use (Beware of counterfeits; buy from official distributors)

Mobil 1
Shell Helix
Castrol EDGE

For Performance / High RPM

Liqui Moly
Motul
AMSOIL
Red Line
WAKO’S
Ravenol

Taiwan Brands

Formosa (台塑)
Kuo Horng (Idemitsu/國宏)
OEM Factory Oils

Brands to Avoid

“Local blends” marketed as foreign “snake oils”.
Brands you’ve never heard of. Search for them on the Mercedes-Benz Bevo site. If the total approval count across all sheets is less than 10, think twice before buying.