Mineral oil
Mobil Rarus 400
For DIN 51506 VDL requirements.
- Consider for typical or demanding conditions, including compressor gears and bearings lubricated by the same oil.
Oil selection tool
Guide · compressor oils
Which air compressor oil? piston and screw compressors
Choose air compressor oil using the manual: compressor type, viscosity and conditions matter. Compare workshop and industrial applications.
In short
Choose compressor oil in the ISO VG grade specified in the manual. Rarus 400 meets most air-compressor needs. Consider synthetic oil for continuous operation at high discharge temperatures, up to 200°C, or rapid oil degradation.
- Lower Rarus 400 grades mainly serve screw and vane compressors.
- For piston units, check the manual; the series includes ISO VG 100 and 150.
- Refrigeration and breathing-air applications require different oils.
Compressor type and oil selection
Compressor type determines which series to compare. Confirm the ISO VG grade in the equipment manual.
| Compressor type | What the manufacturer states | Series and ISO VG grades |
|---|---|---|
| Piston (reciprocating) | Rarus 400 lubricates crankcases and cylinders; Rarus 800 is primarily intended for heavily loaded reciprocating units. | Rarus 400: 427 (100), 429 (150); Rarus 800: 827 (100), 829 (150). |
| Screw and vane | Lower Rarus 400 grades mainly serve rotary units; SHC 1020 is for severe conditions. | Rarus 400: 424 (32), 425 (46), 426 (68); SHC 1020: 1024 (32), 1025 (46), 1026 (68). |
| Axial and centrifugal | Listed among Rarus 400 applications. | Rarus 400; the compressor manufacturer specifies the grade. |
| Refrigeration | Oil must suit the refrigerant. | Separate oil category. |
| Breathing air | None of the three Rarus series is recommended. | — |
Workshop compressor
Choose oil for your workshop compressor
Read oil type, ISO VG grade and quantity from the manual or compressor markings. The manual also gives level-checking instructions.
Mobipol offers Rarus 425 and 427 in 20 l and 208 l packs, among other products. These sizes suit workshops with several units and industrial plants.
Industrial compressor
Mineral or synthetic compressor oil
Rarus 400 meets DIN 51506 VDL and serves most air compressor applications. Consider a synthetic oil where mineral oil loses performance quickly.
Do not use Rarus SHC 1020 where discharge temperature exceeds the oil’s flash point: 245–246°C according to the product data sheet.
Without the manual, give an expert the equipment model.
Send nameplate photo| Property | Rarus 400 | Rarus SHC 1020 | Rarus 800 |
|---|---|---|---|
| Base oil | Mineral; ashless formulation | Synthetic hydrocarbons | Synthetic |
| Compressors | Piston, screw, vane, axial, centrifugal | Mainly screw and vane | Mainly heavily loaded piston units |
| High temperature | Compressed air: max. 220°C according to DIN 51506 | Continuous discharge temperatures up to 200°C | Continuous discharge temperatures up to 200°C |
| Oxidation resistance | Good | Higher than mineral oils | Higher than mineral oils |
| Fire and explosion risk | Reduced through low carbon deposit formation | Lower than with mineral oils | Lower than with mineral oils |
| Seals | — | — | Restrictions include natural rubber, butyl rubber and NBR below 30% acrylonitrile |
| Mixing with mineral oil | — | Reduces performance | Reduces performance |
| ISO VG grades in the shop | 32, 46, 68, 100, 150 | 32, 46, 68 | 100, 150 |
Steps for choosing compressor oil
Start with compressor type and manual requirements. Then check operating conditions, material compatibility and oil monitoring.
Identify the type and model
Start with piston, screw, vane or centrifugal. “Compressor” alone is not enough to select an oil.
Record the manual’s requirements
Note the ISO VG grade and specification. If the manufacturer permits mineral oil and requires DIN 51506 VDL, consider the corresponding Rarus 400 grade.
Describe operation
Continuous use, high discharge temperatures or rapid degradation are reasons to consider SHC 1020 for rotary units or Rarus 800 for piston units.
Check oil and seals
Plan changeover with an expert, considering Rarus 800 material restrictions.
Monitor oil in service
In an industrial plant, test samples and compare successive results. This provides a basis for assessing oil condition.
Compare Mobil compressor oils
Compare Rarus 400 for typical applications with synthetic series for more demanding conditions. Choose the variant according to the compressor manual.
- Full Mobil compressor oil range
- Refrigeration compressor oils
- Which one to choose? Ask an expert
Synthetic oil
Mobil Rarus SHC 1020
For continuous rotary compressor operation.
- Consider for screw or vane units with discharge temperatures up to 200°C and rapid mineral oil degradation.
Synthetic oil
Mobil Rarus 800
For heavily loaded piston compressors.
- Consider where valve deposits occur and reducing fire risk in the discharge system matters.
Avoid compressor oil selection mistakes
Match the product to the compressor and intended air use. Compatibility, temperature and changeover planning matter alongside viscosity.
Mistake
Choosing by number alone
Instead:
Choose compressor oil in the ISO VG grade specified in the manual.
Mistake
Confusing applications
Instead:
Air compressor and refrigeration compressor oils are separate categories.
Mistake
Overlooking the air’s intended use
Instead:
The manufacturer does not recommend any of these Rarus series for breathing-air compressors.
Mistake
Mixing without a plan
Instead:
Mineral oil admixture reduces Rarus SHC 1020 and Rarus 800 performance. Plan the change with an expert.
Mistake
Ignoring temperature limits
Instead:
Rarus SHC 1020 must not operate where discharge temperature exceeds the oil’s flash point.
Have a similar case?
When to change compressor oil
Check the manual for drain intervals, including for small workshop compressors. In industrial plants, also assess oil condition through sample analysis.
Quarterly testing is a starting point. Analysis does not automatically extend the drain interval. Testing includes:
- Viscosity at 40 and 100°C
- Total acid number (TAN) and oxidation resistance reserve (RPVOT)
- Karl Fischer water testing, demulsibility and foam
- MPC and RULER, which help assess varnish risk
Ask for oil selection advice
Provide the compressor type, model and discharge temperature. Our specialist will help choose an oil and reply with a specific product recommendation.
Jan Kowalski
Technical Engineer for Lubricants, Mobipol
“Give me the compressor type and model and the discharge temperature. I will tell you whether mineral oil is enough or a synthetic is worth it.”
Frequently asked questions
Only if the manual permits it. If it requires compressor oil, for example DIN 51506 VDL, use that oil in the specified ISO VG grade.
Only if the equipment manufacturer permits it. Mobil Rarus is an air compressor oil series, not hydraulic oil.
Choose the grade specified by the manual: Rarus 427 and 429 are ISO VG 100 and 150. Consider synthetic Rarus 800 for severe service.
Consider lower Rarus 400 grades: ISO VG 32–68. For continuous operation at high discharge temperatures, check Rarus SHC 1020.
Rarus SHC 1020 and Rarus 800 are compatible with mineral compressor oils, but admixture reduces their performance. Plan the change with an expert.
Follow the equipment manual. In an industrial plant, account for analysis results too; quarterly testing is a starting point, not an oil-change interval.
This is a separate category: see industrial refrigeration compressor oils. This guide does not cover automotive air conditioning.
No. The manufacturer does not recommend Rarus 400, SHC 1020 or Rarus 800 for these applications.
