Mr O-Ring 208 Viton O-Ring 90A 5/8 in ID Pack of 100

In this review the Mr O-Ring 208 Viton O-Ring pack is evaluated for workshop and industrial sealing tasks; the bottom line is that this pack of 100 provides dependable, high-temperature resistance for technicians and hobbyists who need a consistent, AS568-size Viton solution. The reviewer found these o-rings useful where chemical and heat resistance matter, and the confirmed actual dimensions and the firm 90A durometer make them predictable in compression set and sealing performance. For anyone replacing seals exposed to fuel, mineral oil, or elevated temperatures, this pack is a practical, cost-effective choice.

Key Features

• Material: Fluorocarbon rubber (Viton) offers strong resistance to fuels, oils, and many organic solvents for long-lasting seals.
• Temperature range: Rated from -26C to 232C, these o-rings handle both near-freezing and high-temperature applications without rapid degradation.
• Hardness: The 90A durometer provides a firm cross-section that resists extrusion while maintaining a reliable seal under pressure.
• Pack size: Supplied in a pack of 100, this set reduces downtime and ensures spare parts availability for frequent maintenance tasks.
• Size accuracy: The nominal and actual dimensions are listed, allowing accurate selection for AS568-compliant replacements.
• Chemical compatibility: Suitable for petroleum products, diesel blends, silicone oils, and many harsh environments where standard elastomers would fail.

Who It's For

This pack is aimed at mechanics, maintenance technicians, and DIYers who need a dependable, high-temp o-ring in a standard AS568 size for engines, pumps, and hydraulic fittings. The 90A hardness and Viton composition make it especially suited for seals exposed to fuels, mineral oils, and elevated operating temperatures.

Those working exclusively with very soft seals, food-grade systems requiring FDA-certified elastomers, or applications needing extreme flexibility at subzero temperatures should consider alternative materials or hardnesses better matched to those conditions.

Pros & Cons

Pros

• High chemical and temperature resistance from Viton material makes these o-rings durable in harsh environments.
• The 90A durometer yields consistent, predictable sealing performance with lower risk of extrusion under load.
• Pack of 100 offers good value for workshops and frequent service use, minimizing repeat orders.
• Actual dimensions are provided so users can confirm fit before installation.

Cons

• 90A hardness is relatively firm and may not seal as well as softer compounds in low-compression or delicate fittings.
• Not intended for applications requiring specific food-grade or medical certifications.

Specifications

Our Verdict

The Mr O-Ring 208 Viton 90A pack is a strong value for anyone needing AS568-size Viton seals that withstand fuels, oils, and high temperatures. It is best for industrial maintenance and mechanical repairs where a firm, reliable seal is required; buyers who need softer compounds or certified food-grade materials should look elsewhere.

Frequently Asked Questions

Are these o-rings compatible with fuels and biodiesel?
Yes, Viton is designed to perform in petroleum products, diesel blends and biodiesel-compatible environments.

What is the effective temperature range?
They are rated from -26C (-15F) up to 232C (450F) for high-temperature sealing.

Do the sizes follow AS568 standards?
Yes, the product meets the AS568 size standard and both nominal and actual dimensions are provided for confirmation.