Mr O-Ring 268 Viton O-Ring 90A, 8-1/2 in ID (Pack of 5)

In this review the Mr O-Ring 268 Viton o-ring is evaluated for technicians and hobbyists who need a reliable, high-temperature seal. The bottom line: this 90A durometer Viton o-ring is best for petroleum, fuel blends, hydraulic fluids and other aggressive environments because its Fluorocarbon rubber compound resists heat, ozone and many solvents. The pack of five with nominal 8-1/2 in ID and 1/8 in cross-section gives installers spare parts for maintenance jobs, making it a practical choice when chemical resistance and temperature tolerance are the priorities.

Key Features

• Material: Viton (Fluorocarbon rubber) provides strong resistance to fuels, mineral oils and many organic solvents, reducing seal degradation in aggressive fluids.
• Temperature range: Rated from -26C (-15F) to 232C (450F), the o-ring stays serviceable across common industrial high- and low-temperature environments.
• Hardness: The 90A durometer gives a firmer seal that holds shape under pressure and resists extrusion in many sealing applications.
• Size accuracy: Nominal 8-1/2 in ID and 8-3/4 in OD with actual dimensions closely matching the nominal values, helping ensure a proper fit when replacing AS568 sizes.
• Pack quantity: Supplied in a pack of five so you have spares for trouble-shooting, scheduled maintenance or multiple assemblies.
• Chemical versatility: Performs well with petroleum, diesel blends, methanol/ethanol blends, silicone oils, and even in high vacuum and ozone exposure.

Who It's For

This Mr O-Ring product is aimed at maintenance technicians, mechanics and DIYers who repair pumps, valves or fittings exposed to fuels, oils or high temperatures. It is also suited for marine, automotive and industrial equipment where a durable fluorocarbon seal is required.

Those who need very soft or food-grade silicone seals, or who require extreme low-temperature flex below the specified range, should consider other elastomers. If precise specialty tolerances beyond standard AS568 sizing are required, confirm the fit before ordering.

Pros & Cons

Pros

• Excellent chemical resistance to fuels, oils and many solvents extends seal life in harsh environments.
• Wide temperature rating makes it usable in hot engine areas and heated process systems.
• Packed as five pieces, providing immediate spares for repairs and reducing downtime.
• Consistent durometer and closely matching actual dimensions improve reliability of replacements.

Cons

• Higher hardness (90A) means it is firmer and less flexible than softer o-rings, which can be a limitation in applications needing more conformability.
• Not intended for applications requiring food-grade approval or extreme cryogenic service outside the listed temperature range.

Specifications

Material	Viton (Fluorocarbon rubber, FKM)
Durometer	90A
Nominal dimensions	8-1/2 in ID, 8-3/4 in OD, 1/8 in CS
Actual dimensions	8.484 in ID, 8.762 in OD, 0.139 in CS
Metric dimensions	215.49 mm ID, 222.55 mm OD, 3.53 mm CS
Temperature range	-26C (-15F) to 232C (450F)
Pack size	5 pieces

Our Verdict

The Mr O-Ring 268 Viton o-ring is a solid, cost-effective choice for users who need a chemically resistant, high-temperature seal in automotive, industrial and hydraulic applications. Its 90A hardness and accurate dimensions make it reliable for replacement work, and the pack of five adds convenience for maintenance. Choose this if you need durability and chemical resistance; look elsewhere if you require softer or food-grade materials.

Frequently Asked Questions

Is this o-ring compatible with gasoline and diesel?
Yes, the Viton compound is designed to perform well in petroleum products, diesel and common fuel blends.

Does the 90A hardness affect sealing performance?
The 90A durometer makes the ring firmer, which improves extrusion resistance and dimensional stability but reduces flexibility compared with softer compounds.

Will this fit standard AS568 sizes?
Yes, this Viton o-ring is made to match AS568 size standards and the listed actual dimensions closely match the nominal size.