HLP hydraulic oil to DIN 51524-2: choosing ISO VG 46, 68 or 100
HLP hydraulic oil to DIN 51524-2 works in presses, machine tools, lifting gear and many mobile machines. This page explains what the standard requires, how to choose between ISO VG 46, 68 and 100, and which pump and machine maker specifications Elat oils list on their labels.
What DIN 51524-2 specifies for HLP hydraulic oil
DIN 51524 is the German standard for mineral oil-based hydraulic fluids and comes in three parts: Part 1 covers HL oils, Part 2 HLP oils and Part 3 HVLP oils. DIN 51524-2 is therefore the reference for conventional HLP hydraulic oil. The letters follow the German lubricant designation system in DIN 51502: H stands for hydraulic oil, L for additives against corrosion and ageing, and P for additives that reduce wear and raise load-carrying capacity.
The standard sets minimum requirements for a whole range of properties, including wear protection, ageing stability, corrosion protection, air release, foaming, water separation and compatibility with seal materials. Many of the limits vary with the viscosity grade.
Outside Germany, HLP broadly corresponds to category ISO 11158 HM, which likewise describes mineral hydraulic oils with anti-wear additives – although the test requirements of the two standards are not identical in every detail. Elat HLP 46, HLP 68 and HLP 100 list both; on the label, the DIN standard is written as “DIN 51524/2”.
In brief
Part 2 of DIN 51524 covers mineral hydraulic oils of type HLP with additives against wear, corrosion and ageing; internationally, this largely corresponds to category HM under ISO 11158. The right viscosity grade depends on the machine manufacturer’s requirement and on the operating temperature. Elat offers HLP 46, HLP 68 and HLP 100, each with a long list of maker specifications on the label.
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ISO VG 46, 68 or 100: which viscosity grade is right?
The number after HLP is the viscosity grade under ISO 3448. It gives the mid-point kinematic viscosity at 40 °C in mm²/s, with a permitted tolerance of ±10 %. An HLP 46 therefore measures between 41.4 and 50.6 mm²/s at 40 °C, and an HLP 68 between 61.2 and 74.8 mm²/s.
The grade a system needs is set by the manufacturer of the machine, pump or power unit. Within that requirement, operating temperature decides: oil that runs hot usually calls for a higher ISO VG to keep the lubricating film strong, while cold conditions and frequent cold starts favour a lower grade, because thick oil is harder for the pump to draw in.
Do not change grade on your own initiative: oil that is too thin increases internal leakage and wear, while oil that is too thick makes the system sluggish and wastes energy. The product descriptions position Elat HLP 46, 68 and 100 as shown in the table.
| ISO VG | Viscosity at 40 °C | Focus according to product description | Elat product |
|---|---|---|---|
| 46 | 41.4–50.6 mm²/s | industrial and mobile hydraulic systems under normal operating conditions | Hydraulic Oil HLP 46 |
| 68 | 61.2–74.8 mm²/s | applications with higher operating temperatures | Hydraulic Oil HLP 68 |
| 100 | 90–110 mm²/s | highly stressed systems, elevated operating temperatures, slow-running components | Hydraulic Oil HLP 100 |
Elat HLP 46, 68 and 100 hydraulic oils
All three oils list DIN 51524/2 and ISO 11158 HM but differ in some of their maker entries. The entries relevant to this page are highlighted.
Hydraulic Oil HLP 46
ISO VG 46 · Hydraulic Oil
The only one of the three oils to list SEB 181222; also lists SAUER DANFOSS 520L0463.
Hydraulic Oil HLP 68
ISO VG 68 · Hydraulic Oil
According to its product description, intended for applications with higher operating temperatures; lists SAUER DANFOSS 520L0463.
Hydraulic Oil HLP 100
ISO VG 100 · Hydraulic Oil
According to its product description, intended for highly stressed systems; lists CINCINNATI MILACRON P-68, 69, 70.
Also in our range (details on the product pages): Hydraulic Oil HLP 22, Hydraulic Oil HLP 32
Approval or specification?
Only expressly stated manufacturer approvals are marked “Approval”. All other entries are specifications and recommendations as printed on the product label; the entries relevant to this topic are highlighted. For your vehicle or machine, the owner’s manual and the manufacturer’s approval lists always take precedence. If in doubt, we are happy to advise you.
Denison HF-0, Eaton Vickers, Bosch Rexroth: maker specifications on the label
Besides the DIN standard, Elat HLP oils list a long set of specifications from industry and machine building. Many come from makers of hydraulic pumps and motors that assess oils in their own test runs – and manuals often ask for the pump maker’s specification as well as an oil class.
Denison HF-0 is regarded as the most demanding level of the Denison specification, as it covers both vane and piston pumps; HF-2 relates to vane pumps. Eaton Vickers distinguishes M 2950-S for mobile and I-286-S for industrial hydraulics, and the former is often written as Vickers M-2950-S. Bosch Rexroth appears on the label without a document number; the documentation of your component shows whether a particular Rexroth guideline applies.
The three oils do not list identical entries: SAUER DANFOSS 520L0463 appears only on HLP 46 and HLP 68, SEB 181222 only on HLP 46, and each viscosity carries its own Cincinnati Milacron number. Of interest for construction machinery is JCMAS P041 HK, a Japanese standard for hydraulic oil in construction machines, which all three oils list. VDMA 24318 comes from the German machinery association VDMA.
| Label entry | Origin | HLP 46 | HLP 68 | HLP 100 |
|---|---|---|---|---|
| DIN 51524/2 | German HLP standard | yes | yes | yes |
| ISO 11158 HM | International, category HM | yes | yes | yes |
| AFNOR NF E 48-603 (HM), CETOP RP 91 H (HM) | French standard, European CETOP recommendation | yes | yes | yes |
| DENISON HF-0, HF-2 | Pump maker Denison | yes | yes | yes |
| EATON VICKERS M 2950-S, I-286-S3 | Pump maker Eaton Vickers | yes | yes | yes |
| BOSCH Rexroth | Hydraulics maker, no document number | yes | yes | yes |
| SAUER DANFOSS 520L0463 | Mobile hydraulics maker | yes | yes | – |
| SEB 181222 (HLP 46) | Steel industry sheet (Stahl-Eisen-Betriebsblatt) | yes | – | – |
| CINCINNATI MILACRON | Machine tool maker | P 70 | P-69 | P-68, 69, 70 |
| VDMA 24318 | German machinery association | yes | yes | yes |
| JCMAS P041 HK | Japanese construction machinery standard | yes | yes | yes |
| FZG-Test A8, 3/90 failure load stage 12 | Gear test rig | yes | yes | yes |
Choosing hydraulic oil for construction machinery and industrial plants
Whether it is a press on the shop floor or an excavator on site, the selection always follows the same order: first the manufacturer’s requirement, then the operating conditions, and finally quantity and pack size.
- Follow the specification: the manual or lubrication chart gives the oil type and ISO VG, often together with a pump specification such as Denison HF-0 or Eaton Vickers M 2950-S.
- Check the temperature range: stationary plants usually run at steady temperatures, while mobile machines outdoors see wider swings – their manufacturer may specify a different oil type instead of HLP.
- Top up with the same grade: use the viscosity grade that is already in the system. A switch to another product is best done with a complete oil change.
- Fill cleanly: even new oil should be filled through a filter, because servo and proportional valves are sensitive to particles.
- Store containers properly: keep them closed, dry and under cover wherever possible, so that neither water nor dirt can get in.
How HLP differs from HVLP and HLPD, and how oil care and filtration work, is explained in our hydraulic oil guide.
HLP 22 and HLP 32
For systems that call for a lower viscosity, the range also includes Hydraulic Oil HLP 22 and Hydraulic Oil HLP 32. We will provide the specifications of these two oils on request.
Sourcing HLP hydraulic oil for industry, retail and workshops
From the first fill of a new plant to the ongoing needs of a maintenance team, industrial companies, workshops and retailers across Germany obtain Elat hydraulic oil directly from Global Tech Lubricants. Pack sizes run from 1-litre bottles to 1000-litre IBCs and tanker deliveries, with scheduling from our warehouse in Lünen.
Each product page shows the full label details, plus the technical data sheet where we have one. Used hydraulic oil must be disposed of properly as waste oil; we organise collection nationwide through disposal partners with the relevant certification – see our waste oil collection page. For an overview of how supply and the range fit together, see lubricant supply across Germany.
Frequently asked questions
What does HLP mean for hydraulic oil?
HLP denotes a mineral-based hydraulic oil with additives against corrosion and ageing (L) and additives that reduce wear (P). Its minimum requirements are set out in Part 2 of DIN 51524. The number that follows, such as 46 or 68, is the ISO VG viscosity grade.
Is HLP the same as HM to ISO 11158?
Broadly, yes: both designations describe mineral hydraulic oils with anti-wear additives. The test requirements of the two standards are not identical in every detail, however. According to their labels, Elat HLP 46, 68 and 100 list both DIN 51524/2 and ISO 11158 HM.
What is the difference between HLP 46 and HLP 68?
The difference is the viscosity: at 40 °C, HLP 68 is noticeably thicker than HLP 46. Which oil is right is decided by the machine manufacturer, usually depending on pump design and operating temperature. The product description of Hydraulic Oil HLP 68 names applications with higher operating temperatures.
Can I mix HLP 46 and HLP 68?
For topping up, use the viscosity grade that is already in the system. A mixture ends up somewhere between the two grades and no longer matches the manufacturer’s requirement exactly. If you want to change grade permanently, agree it with the manufacturer and replace the oil completely.
Do Elat hydraulic oils have a Bosch Rexroth or Denison approval?
BOSCH Rexroth, DENISON HF-0, HF-2 and EATON VICKERS appear on the label as specifications or recommendations; we do not state a separate manufacturer approval for them. Whether your system requires an oil from a manufacturer’s approval list is set out in that manufacturer’s documentation. Talk to us if you would like us to go through it for your system.
Related topics
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Send us the oil type, ISO VG and required maker specification from your lubrication chart, together with the quantity you need. We will suggest the right Elat hydraulic oil.
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