Mr O-Ring 277 Viton O-Ring 90A Durometer 11-1/2in ID Pack of 5

Our review of the Mr O-Ring 277 Viton O-Ring finds it best suited for technicians and maintenance professionals who need a high-temperature, fuel-resistant sealing solution in a common AS568 size. The single biggest reason to consider these o-rings is their material: 90A durometer Viton (FKM) delivers reliable resistance to fuels, oils, solvents and high heat while retaining good dimensional stability. Packaged as five black rings in the nominal 11-1/2in ID size, these parts are intended for repeated service in automotive, hydraulic and industrial sealing tasks where chemical and thermal resistance matter.

Key Features

• Material: 277 Viton (FKM) composition provides excellent resistance to petroleum products, fuels, and many organic solvents, making it suitable for harsh chemical environments.
• Temperature range: Rated from -26C (-15F) to 232C (450F), allowing use across a wide span of operating temperatures including very high temp air applications.
• Hardness: 90A durometer offers a firm cross-section that resists extrusion while still sealing effectively under pressure in many static and dynamic applications.
• Sized to standards: Nominal AS568-compatible dimensions (11-1/2in ID, 11-3/4in OD, 1/8in CS) make these o-rings easy to match to existing grooves and housings.
• Pack quantity: Sold as a pack of 5, which is convenient for small maintenance runs or keeping spares on hand without buying large bulk quantities.
• Durability: Unlimited shelf-life and strong resistance to ozone and weather help these rings remain serviceable after storage.

Who It's For

These o-rings are aimed at professionals and experienced DIYers who need a chemical-resistant seal for engines, fuel systems, hydraulic fittings or industrial equipment exposed to fuels, mineral oil, silicone oil, or high temperatures. The 90A hardness and Viton material suit applications where exposure to aromatics, solvents or higher operating temperatures is expected.

Those who should look elsewhere include users needing very soft, low-pressure seals (choose a lower durometer elastomer) or anyone requiring specialized elastomers outside the FKM family for extreme acids or bases not listed in the product description.

Pros & Cons

Pros

• Excellent chemical and high-temperature resistance from the Viton FKM compound.
• AS568 nominal dimensions simplify replacement and compatibility with common grooves.
• Pack of 5 provides immediate spares for maintenance tasks.

Cons

• 90A hardness may be too firm for very low-pressure or delicate sealing surfaces where a softer compound is preferred.

Specifications

Our Verdict

The Mr O-Ring 277 Viton 90A o-ring is a practical, cost-effective choice for maintenance professionals who need a durable seal that tolerates fuels, oils and high temperatures. Its AS568-compatible sizing and unlimited shelf-life make it good value for spare parts and repairs, though installers should confirm that 90A hardness is appropriate for their sealing surface.

Frequently Asked Questions

Are these o-rings compatible with gasoline and diesel?
Yes, the Viton FKM compound is specifically noted as performing well with petroleum products, gasoline blends and diesel.

Do the rings meet common size standards?
Yes, the product is intended to meet AS568 nominal size standards for the listed dimensions.

What operating temperatures are supported?
They are rated from -26C (-15F) up to 232C (450F), suitable for many high-temperature applications.