334 Viton O-Ring 90A 2-5/8in ID 3in OD Pack of 25 - High Temp Seal

In this review the Mr O-Ring 334 Viton O-Ring is evaluated for technicians and DIYers who need reliable, high-temperature sealing in fuel, oil, or chemical environments. The bottom line: this pack of 25 90A durometer fluorocarbon rings is best for routine maintenance and bulk replacement where resistance to heat, fuels and solvents matters most. The reviewer found the material consistent with industry expectations and sized to common AS568 tolerances, making these rings a sensible choice when longevity and chemical resistance are priorities.

Key Features

• Material: Viton (FKM) delivers excellent resistance to high temperature, ozone, weather and many organic solvents, reducing premature failure in aggressive environments.
• Hardness: 90A durometer offers a firm sealing surface that holds compression well for static seals while resisting extrusion under moderate pressure.
• Size accuracy: Nominal and actual dimensions are provided so installers can verify fit; actual dimensions read 2.600in ID and 3.020in OD for reliable replacement matching.
• Wide temperature range: Rated from -26C (-15F) to 232C (450F), suitable for applications exposed to very high temperatures or thermal cycling.
• Chemical compatibility: Performs well with petroleum, diesel and biodiesel blends, methanol or ethanol blends, mineral oils, silicone fluids and many acids, making it versatile for industrial service.
• Bulk value: Pack of 25 provides inventory for multiple maintenance cycles or for shops that perform frequent seal replacements.

Who It's For

This Viton o-ring is aimed at maintenance technicians, hydraulic and pneumatic service shops, and industrial users who need a durable seal tolerant of fuels, oils and high temperatures. It is also useful for hobbyists converting equipment to fuel blends or for installations exposed to ozone and weather where a long-lived elastomer is required.

Those who should look elsewhere include users requiring extreme low-temperature flexibility below -26C or applications demanding a softer durometer for dynamic rotary seals; for those cases a different compound or hardness may be a better match.

Pros & Cons

Pros

• Excellent chemical and heat resistance makes these o-rings dependable in aggressive fluid environments.
• 90A durometer provides durable sealing and resistance to extrusion for many static sealing tasks.
• Pack of 25 offers good value for routine maintenance and reduces reorder frequency.
• Provided actual dimensions help confirm proper fit before installation.

Cons

• Relatively hard 90A compound is less suited to very low-temperature flexibility or some dynamic sealing needs.
• Viton is more costly than general-purpose rubbers, so overkill for non-aggressive environments.

Specifications

Material	Viton (FKM)
Durometer	90A
Nominal dimensions	2-5/8in ID, 3in OD, 3/16in CS
Actual dimensions	2.600in ID, 3.020in OD, 0.210in CS
Metric dimensions	66.04 mm ID, 76.70 mm OD, 5.33 mm CS
Temperature range	-26C (-15F) to 232C (450F)
Pack quantity	25

Our Verdict

For anyone needing a dependable, high-temperature resistant seal in contact with fuels, oils or many solvents, these 334 Viton o-rings are a pragmatic choice. The 90A hardness and accurate dimensions match common AS568 replacements, and the pack-of-25 format makes them good value for shops and repeat maintenance. Choose a softer compound only if low-temperature elasticity or dynamic shaft sealing is required.

Frequently Asked Questions

Are these o-rings suitable for fuel blends containing ethanol?
Yes. The Viton compound is stated to perform well with fuels blended with methanol or ethanol and with biodiesel blends.

Do the rings meet AS568 sizing?
They are described as meeting size standards defined by AS568 and actual dimensions are provided to confirm fit.

What is the usable temperature range?
The specified operating range is -26C (-15F) up to 232C (450F), suitable for high-temperature service.