Hydraulic Oil (Synthetic) Resistant O-Rings
Compatibility ratings for 7 O-ring materials in Hydraulic Oil (Synthetic) service
Hydraulic Oil (Synthetic) (Oils & Lubricants) compatibility with the seven most common O-ring elastomers, rated on the standard A/B/C/D scale: A = excellent, B = good, C = fair, D = not recommended. This data also appears in our interactive chemical compatibility chart and is available machine-readable at /api/chemicals.json.
| Material | Rating | Guidance |
|---|---|---|
| NBR | B | good — suitable for most applications |
| FKM | A | excellent — recommended for continuous service |
| EPDM | C | fair — conditional use, verify with testing |
| VMQ | B | good — suitable for most applications |
| PTFE | A | excellent — recommended for continuous service |
| FFKM | A | excellent — recommended for continuous service |
| HNBR | A | excellent — recommended for continuous service |
Why These Ratings
- FKM (A) — documented strengths include “Mineral oils and greases.”
- EPDM (C) — documented weaknesses include “Mineral oils.”
- PTFE (A) — documented strengths include “Fuels and oils.”
- FFKM (A) — documented strengths include “Fuels and oils.”
- HNBR (A) — documented strengths include “Mineral oils.”
Oils & LubricantsService: Concentration & Temperature Notes
Petroleum oils are the easiest service in this catalog for NBR, FKM, HNBR, PTFE and FFKM — all rate A. Two traps remain: EPDM, which swells severely and rates D across every oil row; and synthetic fluids, whose additive chemistry differs from mineral oil — our hydraulic-synthetic row shows EPDM improving to C while NBR drops to B versus mineral hydraulic oil.
Recommended
- FKM O-rings (A)
- PTFE O-rings (A)
- FFKM O-rings (A)
- HNBR O-rings (A)
Use With Caution
- NBR O-rings (B)
- EPDM O-rings (C)
- VMQ O-rings (B)
Avoid
No material is rated D for this chemical.
Related Guides
Related Chemicals (Oils & Lubricants)
Frequently Asked Questions
Is Hydraulic Oil (Synthetic) compatible with FKM (Viton) O-rings?
FKM is rated A for Hydraulic Oil (Synthetic): excellent — recommended for continuous service. Ratings are general guidelines; concentration, temperature and exposure time all affect real-world compatibility, so validate critical applications with ASTM D471 immersion testing.
Is Hydraulic Oil (Synthetic) compatible with NBR (nitrile) O-rings?
NBR is rated B for Hydraulic Oil (Synthetic): good — suitable for most applications. NBR is the lowest-cost elastomer, so when it earns an A or B rating it is usually the economical default; when it rates C or D, do not substitute it for a higher-rated material to save cost.
Can I use PTFE O-rings with Hydraulic Oil (Synthetic)?
PTFE is rated A for Hydraulic Oil (Synthetic): excellent — recommended for continuous service. Remember that PTFE has no elastic memory — in demanding service it needs spring energization or an elastomer core (FEP/PFA encapsulation) to maintain sealing force.
What is the best O-ring material for Hydraulic Oil (Synthetic)?
FKM, PTFE, FFKM, HNBR are rated A (excellent) for Hydraulic Oil (Synthetic) in our compatibility data and are the recommended starting point for material selection. Final selection should also account for operating temperature, pressure and whether the seal is static or dynamic.
Can I use EPDM O-rings with Hydraulic Oil (Synthetic)?
EPDM is rated C for Hydraulic Oil (Synthetic): fair — conditional use, verify with testing. Always confirm the specific fluid concentration and temperature before specifying EPDM for this service.
Need O-Rings for Hydraulic Oil (Synthetic) Service?
Send us your fluid, concentration and temperature — our engineers will confirm the right compound. MOQ 1 piece.