Mr O-Ring 334 Viton O-Ring 90A Durometer, 2-5/8 in ID Pack of 10

In this review the Mr O-Ring 334 Viton O-Ring (90A) is evaluated for technicians, hobbyists, and maintenance pros who need a small supply of high-temperature, fuel-resistant seals. The bottom line: these o-rings deliver consistent sizing and excellent chemical and heat resistance, making them a reliable choice where Viton performance is required. The pack of 10 simplifies repeat repairs while the nominal and actual dimensions show the manufacturer pays attention to fit, so installers can expect predictable sealing in demanding petroleum, fuel, hydraulic and high temperature applications.

Key Features

• Material: Made from Viton (FKM) which provides outstanding resistance to fuel, oils and many solvents, reducing seal failures in chemical environments.
• Hardness: The 90A durometer offers a firm seal that resists extrusion and maintains shape under compression for durable service life.
• Temperature range: Rated from -26C to 232C (-15F to 450F) so the o-ring works across a wide span of low to very high temperature applications.
• Pack size: Supplied in a pack of 10 which is convenient for maintenance tasks and small projects without buying large bulk quantities.
• Size accuracy: Nominal and actual dimensions are provided (2-5/8 in nominal vs 2.600 in actual ID), helping confirm fitment for assemblies that require tight tolerances.
• Standards: Designed to meet AS568 size definitions so it integrates with common hardware that references standard o-ring sizes.

Who It's For

These o-rings suit maintenance technicians, mechanics, and fabricators who work with fuels, oils, hydraulic fluids, or exposed high-temperature air systems and need a compact quantity for repairs. The chemical resistance of Viton makes them particularly useful for diesel, biodiesel blends, methanol or ethanol blends, and mineral oil systems.

They are less appropriate for applications requiring very soft seals (lower durometer) or where nonfluorocarbon materials are specified for compatibility with particular elastomers; users needing different hardness or materials should look for alternative rubber compounds.

Pros & Cons

Pros

• High chemical and temperature resistance from the Viton material reduces downtime from seal degradation.
• 90A durometer delivers a firm, durable seal suitable for pressure and mechanical stress.
• Actual and metric dimensions are listed, improving confidence when matching to grooves or housings.
• Pack of 10 covers multiple repairs without excess inventory.

Cons

• Higher durometer means the o-ring is firmer and may not seal as readily in very low compression groove designs.
• Viton is a specialty rubber and may be overkill or more costly where general-purpose elastomers would suffice.

Specifications

Material	Viton (FKM)
Durometer	90A
Nominal dimensions	2-5/8 in ID, 3.000 in OD, 3/16 in CS
Actual dimensions	2.600 in ID, 3.020 in OD, 0.210 in CS
Metric dimensions	66.04 mm ID, 76.70 mm OD, 5.33 mm CS
Temperature range	-26C (-15F) to 232C (450F)

Our Verdict

The Mr O-Ring 334 Viton 90A in a pack of 10 is a solid choice for professionals who need reliable, high-temperature and fuel-resistant seals in a standard AS568 size. Its measured dimensions and robust chemical resistance make it good value for repair kits and maintenance tasks where longevity and predictable fit matter.

Frequently Asked Questions

Are these o-rings compatible with fuels and biodiesel?
Yes, Viton (FKM) is formulated to perform well with petroleum, gasoline blends, diesel and biodiesel, and many organic solvents.

What temperature range will they handle?
They are rated from -26C (-15F) up to 232C (450F), suitable for many high-temperature sealing uses.

Do the sizes follow standard dimensions?
Yes, the product lists nominal and actual dimensions and is made to match AS568 size standards for interchangeability.