Lubrication Consulting / 5 min
How to Determine an Industrial Oil Equivalent: An ISO VG and Specification Matching Guide
You may be looking for an equivalent to the oil used in your machinery due to supply-chain issues or cost optimization. In industrial oils, however, the concept of equivalence isn't just about switching brands — it relies entirely on the technical data (specifications) matching, point by point.
Published by: Rotek Technical Content Team
Content is published based on manufacturer technical documentation and equipment requirements as the basis for final selection. This is general guidance and does not replace equipment-specific manufacturer approval.
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- - Step 1: Matching ISO VG (Viscosity)
- - Step 2: Base Oil Technology (Mineral vs. Synthetic)
- - Step 3: Performance Class and Additive Package
- - Step 4: Machine Manufacturer (OEM) Approvals
Step 1: Matching ISO VG (Viscosity)
The first and most non-negotiable rule in choosing an equivalent is kinematic viscosity (typically the ISO VG class measured at 40°C). If your system requires an ISO VG 46 hydraulic oil, the equivalent product must be exactly ISO VG 46. The viscosity index (VI) then confirms whether the new oil shows a resistance to temperature change similar to, or better than, your old oil.
Step 2: Base Oil Technology (Mineral vs. Synthetic)
Even if the label shows the same viscosity, oils can have different base oils. A high-performance synthetic (PAO or PAG) oil might be offered in place of a standard mineral gear oil, or vice versa. The base oil type must be compatible with your machine's operating temperature and seal (sealing element) materials.
Step 3: Performance Class and Additive Package
Matching viscosity alone isn't enough. In hydraulic systems, for example, the oil may need to be ashless or have zinc-based anti-wear (AW) additives. For gear oils, whether the extreme-pressure (EP) additive level meets DIN 51517 Part 3 (CLP) or AGMA 9005 standards must be checked.
Step 4: Machine Manufacturer (OEM) Approvals
Especially in sensitive compressor, turbine or servo-valve systems still under warranty, it should be checked whether the equivalent oil under consideration is approved by the machine manufacturer (OEM - Original Equipment Manufacturer). Note that however similar the data looks on paper, final suitability requires OEM approval or an expert field assessment. Send us your current product's brand, code and label information so our technical team can evaluate the correct match.
Frequently Asked Questions
Is any brand's oil with the same viscosity a full equivalent?
No, two oils with the same viscosity (for example ISO VG 68) may not be full equivalents. One could be a standard anti-wear mineral oil, while the other could be a synthetic oil resistant to very high temperatures or one with special detergent additives.
Which documents should be checked when selecting an equivalent?
When matching an equivalent, you should review the oil's Technical Data Sheet (TDS), not its Safety Data Sheet (SDS). The TDS contains kinematic viscosity, flash point, pour point and international standards (DIN, ISO).
Can I trust online equivalent (cross-reference) charts?
Old or unsourced cross-reference charts online generally match products only on viscosity and general application, which is risky. Your equipment's specific requirements (for example, food compliance or EP additives) may not always appear in these charts.
Can I use an oil other than the brand specified in the machine's manual?
Yes. Machine manufacturers generally recommend a specific brand due to commercial agreements. What matters isn't the brand itself, but whether the new oil meets the specifications that brand provides (for example DIN 51524 Part 2 - HLP).