SN150 and SN500 base oils: the complete buyer’s guide
A practical, evidence-led guide for lubricant blenders, importers and industrial buyers choosing between lighter SN150 and heavier SN500.
8 min read · Reviewed 9 September 2026
SN means Solvent Neutral. In trade, SN150 and SN500 describe relative viscosity families—not an exact guaranteed viscosity and not an API engine-oil service category.
SN150 is the lighter, more fluid option and is often considered for hydraulic, circulating, process and lighter lubricant blends. SN500 is heavier and commonly used to build viscosity in engine, gear and industrial-oil formulations after technical qualification.
Published producer reference specifications
Examples from ExxonMobil virgin Group I product data—not universal SN limits. The producer TDS and batch-specific COA govern every transaction.
Re-refined products may be sold under the same trade name with different viscosity windows. A sheet showing 45–50 mm²/s at 40°C and 7–8 mm²/s at 100°C therefore describes a heavier supplier-specific cut, not the published virgin SN150 example above. It must be offered against its exact specification, process and batch COA—not by the SN150 name alone.
How virgin SN base oil is produced
Virgin material starts with refinery streams and is separated and finished to reach the required viscosity, low-temperature and stability profile.
- Atmospheric and vacuum distillation
- Solvent extraction or equivalent upgrading
- Dewaxing
- Hydrofinishing / final treatment
- Fractionation and batch quality control
How re-refined base oil is produced
Modern re-refining is more than filtering used oil. Product quality depends on feed acceptance, separation technology, final finishing and disciplined batch control.
- Feedstock acceptance and segregation
- Filtration, dehydration and light-end removal
- Vacuum distillation with WFE/TFE where applicable
- Hydrotreating, solvent or adsorption finishing
- Fractionation, storage and batch COA release
COA tests a serious buyer should review
Kinematic viscosity at 40°C / 100°C
Confirms the grade and supports blend calculations.
Viscosity index
Shows how viscosity changes with temperature.
Flash point
Important for handling, storage and volatility screening.
Pour point
Indicates low-temperature flow behaviour.
Colour
Useful for appearance control, but never a complete quality verdict.
Water / TAN / metals
Screens contamination, oxidation and residual elements.
Common buying mistakes
- Buying on colour alone
- Treating every SN150 or SN500 offer as identical
- Accepting a generic COA instead of the shipment batch
- Ignoring application trials and additive compatibility
- Leaving origin, packaging, inspection and Incoterm undefined
Packaging and transport
Common options include bulk tanker, ISO tank, flexitank, IBC and drums. For SN500, ambient temperature and viscosity can affect pumping and discharge; heating must follow the supplier’s SDS and operating instructions.
Technical note: the table reports named producer examples. It is not a universal specification. API base-oil Group I/II/III classification also requires saturates, sulfur and VI—not VI alone.
Frequently asked questions
Is virgin always better than re-refined?
Not automatically. Fitness depends on the required specification, process control, batch consistency and application validation.
Can SN150 and SN500 be blended?
Often yes, but the blend must be calculated and tested against the target viscosity and finished-lubricant requirements.
What should an RFQ include?
Grade, virgin or re-refined preference, target specification, monthly volume, destination, packaging, application and required inspection.
Technical references
ExxonMobil — Americas SN 150 product dataExxonMobil — AP/E SN 500 product dataASTM — Petroleum test methodsAPI 1509 — Base oil grouping criteriaRequest a document-led quotation
Send the target grade, specification, volume, destination and packaging. We will align the enquiry with current TDS, SDS and batch COA availability.
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