334 O-Ring Viton 90A 2-5/8in ID 3in OD Pack of 10 - Chemical & Heat

In this review the 334 O-Ring made of black Viton is examined for general sealing work where chemical and heat resistance matter most. The bottom line is that this pack of 10 O-rings is best for technicians, hobbyists, and maintenance pros who need a compact supply of durable seals that hold up to fuels, oils, and high temperatures. It stands out because the 90A durometer and fluorocarbon material deliver reliable compression and resistance in harsh environments, making it a useful standard-size replacement when compatibility is a concern.

Key Features

• Material: Viton fluorocarbon elastomer offers strong resistance to fuels, oils, ozone, and weathering, which extends service life in contaminated environments.
• Hardness: 90A durometer gives a firmer seal that resists extrusion and deformation under pressure, useful for static and some dynamic sealing points.
• Temperature range: Rated from -15 degrees F to 450 degrees F so it can be used on engines, heaters, and other high-heat applications without rapid degradation.
• Standard size: AS568A 334 size (2-5/8in ID, 3in OD) matches common aerospace and industrial dimensions for straightforward replacement.
• Round cross-section: Classic O-ring geometry forms a continuous seal between overlapping cylindrical surfaces for broad compatibility.
• Pack quantity: Supplied as a pack of 10, giving spare parts on hand for repairs and repeat maintenance tasks.

Who It's For

The 334 Viton O-ring is aimed at users who need a chemically resistant, high-temperature seal in a commonly used AS568A size, including automotive repair, HVAC, spa heater maintenance, hydraulic fittings, and small industrial equipment. It suits mechanics and maintenance staff who want a durable spare part that handles fuels, silicone oils, and many hydrocarbons without swelling or rapid wear.

Those who should look elsewhere include applications that expose seals to low molecular weight organic acids, strong alkalis, or concentrated amines where Viton can be vulnerable, and situations that require a much softer durometer than 90A for delicate low-pressure seals.

Pros & Cons

Pros

• Excellent chemical and fuel resistance for compatibility with a wide range of fluids and solvents.
• High heat tolerance makes it suitable for engine and heater sealing jobs up to 450 degrees F.
• Firm 90A hardness resists deformation and provides a dependable sealing surface under compression.
• Pack of 10 offers good value and immediate replacements for common maintenance needs.

Cons

• Firm durometer may not seal well in very low-pressure or delicate applications where a softer O-ring is preferred.
• Like all Viton, it can be vulnerable to certain chemicals such as some organic acids, ammonia, and strong alkalis.

Specifications

Brand	Mr O-Ring
Material	Viton (fluorocarbon elastomer)
Durometer	90A
Inner diameter	2-5/8 in
Outer diameter	3 in
Cross-section width	3/16 in
Temperature range	-15 degrees F to 450 degrees F

Our Verdict

The 334 Viton 90A O-ring pack is a practical, value-oriented choice for anyone needing a heat- and fuel-resistant standard-sized seal. It is best for mechanical and industrial repairs where durability and chemical compatibility matter, and the pack of 10 reduces downtime by keeping spares on hand. Buyers should confirm chemical compatibility for niche exposures, but for most automotive and equipment sealing tasks this is a dependable option.

Frequently Asked Questions

Is this size compliant with aerospace sizing?
Yes, the O-ring follows AS568A sizing for the 334 standard, making it compatible with equipment that references that aerospace size system.

Can it be used with fuel and hydraulic fluids?
Yes, Viton is compatible with many fuels, silicone oils, aromatic and aliphatic hydrocarbons, and non-flammable hydraulic fluids, which is why it is commonly chosen for those systems.

Will it handle high temperatures from heaters or engines?
Yes, the rated temperature range to 450 degrees F makes it suitable for many heater and engine sealing applications.