FKM vs NBR vs EPDM: which rubber for seals and hoses?
Buyer guide · Riddhi Polymers · Updated 2026-09-29
Short answer: Choose NBR for oils, greases and fuels at moderate temperatures and low cost; EPDM for water, steam, brake fluid, weather and ozone, but never for mineral oils or fuels; and FKM when you need oil, fuel and chemical resistance at high temperatures (up to about 200°C and beyond), at a higher price.
Side-by-side comparison
| Property | NBR (nitrile) | EPDM | FKM (fluoroelastomer) |
|---|---|---|---|
| Typical service temperature | about −30 to +100°C (up to ~120°C short term) | about −45 to +150°C | about −20 to +200°C (some grades higher) |
| Mineral oils and greases | Very good | Poor | Excellent |
| Petrol and diesel | Good | Poor | Excellent |
| Hot water and steam | Fair | Excellent | Fair to good (peroxide-cure grades better) |
| Glycol brake fluid | Poor | Excellent | Poor |
| Ozone and weathering | Poor unless protected | Excellent | Excellent |
| Relative cost | Low | Low | High |
Ranges are typical for standard grades; exact limits depend on the grade, compound and application.
Quick selection guide
- Engine oil, hydraulic oil, fuel lines at moderate temperature: NBR.
- Radiator and coolant hoses, weatherstrips, brake system parts, steam: EPDM.
- Fuel injectors, turbo hoses, shaft seals and O-rings in hot oil or fuel: FKM.
- Oil resistance with better heat and ozone than NBR, at lower cost than FKM: consider HNBR or ACM.
FKM cure systems
Bisphenol-cured FKM gives the best compression set and is standard for O-rings and seals. Peroxide-cured FKM resists steam, hot water and some aggressive fluids better. FFKM (perfluoroelastomer) is used where chemical resistance must be near universal.
Frequently asked questions
Can EPDM be used with engine oil?
No. EPDM swells badly in mineral oils and fuels. Use NBR, or FKM at higher temperatures.
Is FKM the same as Viton?
Viton is a brand name for FKM fluoroelastomer. FKM is the generic ASTM designation, and several producers make equivalent grades.
Which rubber is best for radiator hoses?
EPDM is the standard material for radiator and coolant hoses because it resists hot water-glycol coolant, heat and ozone.
Related products and industries
- FKM and fluoroelastomer supplier
- Synthetic rubber and polymer supplier
- Raw materials for automotive rubber parts
Need help choosing a grade?
Riddhi Polymers has supplied rubber raw materials to 400+ manufacturers across South India since 2009. Tell us your application and we will suggest grades to trial. Request a quote, call +91 98418 19109 or email sales@riddhipolymers.com.
