Technical Specifications
| Property | Unit | Typical Value | Test Method |
|---|---|---|---|
| Appearance | Brownish-red viscous liquid | ||
| Density at 20°C | kg/m³ | 985 | ASTM D4052 |
| Viscosity at 100°C | mm²/s | 80 | ASTM D445 |
| Flash point | °C | 180 | ASTM D93 |
| TBN | mgKOH/g | 107 | ASTM D2896 |
| Calcium | % | 2.70 | ASTM D4951 |
| Magnesium | % | 0.52 | ASTM D4951 |
| Zinc | % | 0.68 | ASTM D4951 |
| Phosphorus | % | 0.61 | ASTM D4951 |
| Nitrogen | % | 0.84 | ASTM D3228 |
| Molybdenum | % | 0.07 | ASTM D4951 |
* Typical values from batch production. Batch-specific COA available on request.
Technical content reviewed by the CheMost additives team · Specifications last reviewed
Application Data
Recommended Treat Rate
8.5–8.9 wt% depending on target API level (SM/SN)
What Is the API SN/SM Gasoline Engine Oil Additive Package (PA3066N)?
CheMost PA3066N is a gasoline engine oil additive package built for API SN and SM — a single concentrate carrying the detergent, dispersant, antiwear and friction-control functions a passenger-car crankcase oil needs. It is a brownish-red viscous liquid with a Total Base Number (TBN) of 107 mgKOH/g, 0.68% zinc, 0.84% nitrogen and 0.07% molybdenum.
SN and SM are the two API service categories immediately below SP, still current and widely specified for the passenger-car fleet already on the road. PA3066N is formulated to those two targets and is published at a different treat rate for each.
PA3066N is supplied as a concentrate for Group I, Group II or Group III base oils. The blender adds a viscosity index improver plus any remaining functional additives separately (see Formulating With PA3066N below).
How PA3066N Protects a Gasoline Engine
Acid neutralisation
A TBN of 107 mgKOH/g (ASTM D2896) is the alkaline reserve that neutralises acidic combustion and oxidation by-products. Because the published treat rate differs by target level, so does the TBN this package contributes — see the treat-rate table below.
Deposit and sludge control
0.84% nitrogen (ASTM D3228) is consistent with nitrogen-containing ashless dispersant chemistry, which is commonly used to keep soot and oxidation products suspended so they cannot agglomerate into sludge or varnish — a requirement both SN and SM tightened over earlier categories.
Antiwear protection
0.68% zinc and 0.61% phosphorus (both ASTM D4951) are consistent with zinc dialkyldithiophosphate (ZDDP)-type antiwear chemistry, which is commonly associated with sacrificial tribofilm formation on loaded surfaces in crankcase oils.
Molybdenum contribution
0.07% molybdenum (ASTM D4951) is consistent with a supplementary friction-reducing role alongside the zinc/phosphorus antiwear chemistry.
API SN and SM — Coverage and Current Status
PA3066N is built for API SN and SM. API introduced SM in 2004, adding protection for engines with higher operating temperatures and increased power density plus tighter sludge and varnish control; SN followed in 2010, adding further high-temperature deposit protection, better seal compatibility and (in its Resource Conserving variant) fuel-economy credit. API lists both SN and SM as Current (checked against API’s own oil-categories page, 2026-08-26): SN “for 2020 and older automotive engines” and SM “for 2010 and older automotive engines.” PA3066N does not cover API SP, and it is not offered as doing so — SL and SF data are not part of this grade’s published specification.
Service-category performance is a property of the fully formulated finished oil, not of an additive package on its own. PA3066N is used in formulations targeting API SN or SM; final qualification depends on your base oil, viscosity modifier and complete additive slate.
PA3066N Applications in Passenger Car Motor Oil
Current-fleet gasoline engine oils
Passenger-car oils targeting API SN or SM — the two service categories most widely specified for vehicles already in service.
Wide viscosity coverage
Blend with a viscosity index improver to reach the required SAE grade — PA3066N is supplied as a concentrate and does not include one.
Group I–III base oil formulations
Suitable for Group I and Group II or Group III base stocks; exact matching suitability depends on the specific base oil and should be confirmed with our technical team.
Aftermarket and workshop fills
SN- and SM-level oils remain the common specification for general-purpose passenger-car service, making this a broad-coverage choice for blenders serving that installed base.
PA3066N Treat Rate by API Service Level
PA3066N is published at a different treat rate for each target service level:
| Target API level | Treat rate | TBN contributed* | Zn contributed* | Mo contributed* |
|---|---|---|---|---|
| SM | 8.5% | 9.1 mgKOH/g | 578 ppm | 60 ppm |
| SN | 8.9% | 9.5 mgKOH/g | 605 ppm | 62 ppm |
SN calls for a marginally higher treat rate than SM (8.9% vs 8.5%), consistent with SN’s tighter high-temperature deposit and seal-compatibility requirements.
Treat rate is a starting point tied to your base oil and the rest of your additive slate. Matching suitability varies with the base oil used — confirm your formulation with our technical team before production blending.
Formulating With PA3066N — What You Still Need to Add
PA3066N is an additive package, not a fully formulated additive system. Additional functional additives — defoamer additives, pour point depressants, thickening agents or viscosity index improvers — need to be added during use. The exact selection depends on the base oil and target grade:
Viscosity index improver
Needed to reach the target SAE grade. See EPM or liquid OCP — the choice affects shear stability and the final VI.
Defoamer
Where foam control is needed, see PDMS silicone defoamer or our silicone-free option for systems sensitive to silicone carry-over.
Pour point depressant
Whether one is needed depends on the base oil and low-temperature target. See polymethacrylate (PMA) pour point depressant.
Thickener, where specified
Whether one is used depends on the viscosity grade being built.
Browse the full range on the passenger car motor oil additive packages hub, or the individual additive components catalogue.
Documentation, Qualification & Regulatory Support
Regulatory documentation
REACH, TSCA and country-specific market registration documentation support available on request.
Third-party inspection
SGS / Intertek / BV pre-shipment inspection can be arranged on request.
Custom grades & packaging
Custom package variants and packaging formats can be discussed with our technical team.
Formulation support
Treat-rate calculation and base-oil compatibility guidance — matching suitability varies with the base oil used, so confirm with our team.
COA, SDS and certificate of origin are provided with every shipment. Request full documentation or a sample — enquiries are answered within 12 hours.
Packaging, Supply and Lead Time
Packaging
200 kg metal drum · 1000 kg IBC tank.
Storage
Dry, clean, well-ventilated warehouse. Maximum storage temperature 50°C; maximum blending temperature 70°C. Shelf life 36 months at ambient temperature.
Minimum order
One drum or one IBC — no minimum order value.
Incoterms & ports
FOB · CIF · EXW from all major Chinese ports.
Stocked and shipped worldwide, typical lead time 1–15 days; 36-month shelf life; samples and quotations answered within 12 hours.
Frequently Asked Questions
What is the difference between API SN and SM oil classifications?
SM, introduced in 2004, added protection for engines with higher operating temperatures and increased power density plus tighter sludge and varnish control. SN, introduced in 2010, built on SM with further high-temperature deposit protection, improved seal compatibility, and — in its Resource Conserving variant — a fuel-economy credit. Both remain API Current categories.
Are API SN and SM still current?
Yes. API lists both as Current on its own oil-categories page (checked 2026-08-26): SN “for 2020 and older automotive engines,” SM “for 2010 and older automotive engines.”
How much PA3066N is needed, and does it differ by target level?
Yes — 8.5% of the finished oil for API SM and 8.9% for API SN. The higher SN figure reflects SN’s tighter high-temperature deposit and seal-compatibility requirements. Final treat rate should be confirmed against your specific base oil and additive slate.
What else has to be added besides PA3066N?
Additional functional additives — defoamer additives, pour point depressants, thickening agents or viscosity index improvers — need to be added during use. Which ones you need depends on your base oil and target grade. PA3066N is an additive package, not a fully formulated additive system.
Does PA3066N cover API SP or SL?
No. PA3066N’s published specification covers only API SN and SM. For the current top gasoline category, see our API SP gasoline engine oil additive package.