Mr O-Ring 374 Viton O-Ring 90A Durometer Pack of 10 - Durable Seal

In this review the Mr O-Ring 374 Viton O-Ring pack is evaluated for workshop and industrial sealing needs; the bottom line is that it is a reliable, high-temperature sealing option for users who need chemical resistance and consistent sizes. The reviewer found these 90A durometer Viton rings well suited for applications involving fuels, oils, and high temperature air where a durable elastomer is required, and appreciates that the pack of 10 supplies multiple replacements. It is best for technicians and maintenance staff who require a stable, heat- and chemical-resistant seal rather than a low-cost disposable option.

Key Features

• Material: Made from Viton (FKM), the o-ring resists a broad range of chemicals and fuels and holds up to aging from ozone and weather.
• Temperature Range: Rated from -26C to 232C, it provides reliable sealing across cold starts and very high temperature service conditions.
• Durometer: The 90A hardness gives a firm sealing surface that maintains shape under compression and suits dynamic and static sealing duties.
• Size Accuracy: Nominal and actual dimensions are listed so installers can match existing AS568 sizes with confidence to avoid fitment surprises.
• Pack Quantity: Supplied as a pack of 10, which is convenient for repeat repairs, spares inventory, or multi-point assemblies.
• Compatibility: Performs well in petroleum products, methanol or ethanol blends, biodiesel, silicone oils, and many solvents commonly found in industrial systems.

Who It's For

The Mr O-Ring 374 Viton is aimed at maintenance technicians, HVAC and hydraulic specialists, and small industrial shops that need a robust, high-temperature resistant o-ring that meets AS568 size standards. Its resistance to fuels, oils, ozone, and high temperatures makes it particularly useful in engine compartments, fuel systems, and high-vacuum equipment.

It may not be the best choice for consumers who need a very soft, low-durometer seal for delicate plumbing fixtures or for applications requiring food-grade elastomers. For light-duty or low-temperature home repairs, a less expensive material might be adequate.

Pros & Cons

Pros

• High chemical and temperature resistance from Viton material gives long-term durability in aggressive environments.
• 90A durometer provides firm, reliable sealing for both static and many dynamic applications.
• Pack of 10 reduces downtime by keeping spare seals on hand for repairs or replacements.
• Actual and metric dimensions are provided to ensure accurate size matching with existing hardware.

Cons

• Higher durometer and specialty material cost more than generic nitrile o-rings, which may be unnecessary for simple home repairs.
• Not intended for food-contact or some specialty chemical exposures not listed in the specifications.

Specifications

Material	Viton (FKM)
Durometer	90A
Nominal Dimensions	9-1/4 in ID, 9-5/8 in OD, 3/16 in CS
Actual Dimensions	9.225 in ID, 9.645 in OD, 0.210 in CS
Metric Dimensions	234.32 mm ID, 244.98 mm OD, 5.33 mm CS
Temperature Range	-26C (-15F) to 232C (450F)
Pack Quantity	10

Our Verdict

The Mr O-Ring 374 Viton 90A pack is a sensible buy for professionals and serious hobbyists who need a resilient seal that tolerates heat, fuels, and many solvents; the precise dimensions and pack size make maintenance planning easy. It is good value where durability and chemical resistance are required, though it is a premium option compared with basic elastomers for low-demand uses.

Frequently Asked Questions

Are these o-rings compatible with fuel and biodiesel?
Yes, the Viton material is rated for petroleum, diesel and biodiesel blends, and many fuel blends including methanol or ethanol mixes.

Do the o-rings meet common sizing standards?
Yes, these rings are sized to AS568 standards and include both nominal and actual dimensions for accurate matching.

Can they be used at high temperature?
They are rated to 232C (450F), making them suitable for many high-temperature sealing applications.