Mr O-Ring 403 Viton O-Ring 90A Durometer - Pack of 5

In this review the Mr O-Ring 403 Viton O-Ring is evaluated for workshop and industrial sealing tasks where chemical and temperature resistance matters. The bottom line: this pack of five 90A durometer Viton o-rings is best for technicians, mechanics and OEMs who need durable seals that resist fuels, oils and high heat up to 232C; it stands out for its material performance and AS568-compatible sizing. The reviewer found the rings predictable in hardness and size, making them a sensible choice when compatibility with petroleum products and high-temperature air is required.

Key Features

• Material: Made from Viton (FKM), the o-ring offers excellent resistance to high temperature, ozone and many organic solvents.
• Durometer: The 90A hardness provides a firm sealing surface that resists extrusion in demanding mechanical applications.
• Temperature range: Rated from -26C to 232C, these rings are suitable for both low-temperature and very high-temperature sealing tasks.
• Size accuracy: Nominal and actual dimensions are provided so users can match the 1.725 in ID and 2.275 in OD rings to existing hardware without guesswork.
• Chemical compatibility: Performs well with petroleum, diesel, biodiesel blends, methanol or ethanol blends, mineral oils and many chemicals commonly found in industrial settings.
• Pack quantity: Supplied as a pack of 5, convenient for small repairs, prototypes or short production runs.

Who It's For

The Mr O-Ring 403 Viton is aimed at professionals and hobbyists who need a reliable high-performance seal for engines, pumps, hydraulic fittings and fuel systems where exposure to fuels, silicones or high temperatures is expected. It is particularly useful for maintenance shops, industrial repair technicians and designers specifying AS568 sizes.

Those who should look elsewhere include applications requiring extreme flexibility at very low durometer values or food-grade elastomers, since this product is a 90A Viton formulation intended for chemical and temperature resistance rather than soft sealing or regulated food-contact use.

Pros & Cons

Pros

• Excellent high temperature and chemical resistance from the Viton (FKM) compound.
• Consistent 90A hardness gives predictable sealing performance under pressure and heat.
• Clear nominal and actual dimensions reduce fitment uncertainty for AS568-compatible applications.

Cons

• At 90A durometer the rings are relatively stiff, which may not suit applications that require very soft or highly conformable seals.

Specifications

Our Verdict

The Mr O-Ring 403 Viton 90A pack is a practical choice for anyone needing durable, heat- and chemical-resistant seals in workshop or industrial settings. Its clear sizing, AS568 compatibility and broad chemical tolerance make it good value for maintenance tasks and small production runs; choose a softer compound if extreme flexibility or food-contact certification is required.

Frequently Asked Questions

Are these o-rings compatible with diesel and biodiesel blends?
Yes, the Viton compound is specified as performing well with diesel and biodiesel blend exposure.

What temperature range will these o-rings tolerate?
They are rated from -26C (-15F) up to 232C (450F), suitable for high-temperature applications.

Do the rings match AS568 sizes?
Yes, the product is offered to meet AS568 size standards and includes both nominal and actual dimensions for fit confirmation.