Mr O-Ring 434 Viton O-Ring 90A Durometer 5-5/8 in ID Pack of 10

In this review the Mr O-Ring 434 Viton O-Ring (90A durometer, pack of 10) is evaluated for common sealing tasks where chemical resistance and temperature tolerance matter. The bottom line: this set is for mechanics, technicians and maintenance crews who need consistent, AS568-size Viton rings that resist fuels, oils and high heat; the single biggest reason to buy is the combination of 90A hardness and Viton's broad chemical and temperature resistance, which makes these o-rings reliable in demanding fluid and high-temperature environments.

Key Features

• Material: 434 Viton (FKM) gives excellent resistance to petroleum fuels, hydraulic fluids and many solvents for long-lasting seals.
• Durometer: 90A hardness provides a firm sealing surface that resists extrusion and maintains shape under pressure for durable performance.
• Dimensions: Nominal 5-5/8 in ID and 6-1/8 in OD with actual 5.600 in ID and 6.150 in OD for predictable fit in AS568 size applications.
• Temperature range: Rated from -26C (-15F) to 232C (450F), making these o-rings suitable for high-temperature air and many engine and process environments.
• Pack size: Supplied as a pack of 10, convenient for routine maintenance, quick replacements, or small projects without buying bulk.

Who It's For

The Mr O-Ring 434 Viton 90A is aimed at professionals and experienced DIYers who need a resilient seal for fuel systems, hydraulic equipment, or applications exposed to high heat, ozone and aggressive oils. Its AS568-compatible dimensions make it appropriate for repair shops, industrial maintenance, and HVAC technicians who want consistent, repeatable replacements.

Those who should look elsewhere include users who need a very soft, low-durometer o-ring for delicate sealing or extremely low-temperature service below -26C, and anyone requiring non-fluorocarbon materials for specific chemical compatibilities not covered by Viton.

Pros & Cons

Pros

• High chemical and heat resistance from 434 Viton makes these o-rings suitable for fuels, oils and many solvents.
• 90A durometer gives a robust seal that resists deformation under pressure and repeated cycles.
• AS568-compatible nominal and actual dimensions provide reliable fit for common standard housings and grooves.
• Pack of 10 is practical for maintenance kits and routine replacements.

Cons

• Viton is not ideal for extremely low-temperature applications below the stated -26C range.
• The 90A hardness may be firmer than desired for very delicate sealing interfaces requiring softer compounds.

Specifications

Our Verdict

The Mr O-Ring 434 Viton 90A pack of 10 is a practical, cost-effective choice for technicians who need durable, heat- and chemical-resistant seals in standard AS568 sizes. Its combination of 90A hardness and Viton chemistry delivers reliable performance in fuel, oil and high-temperature systems, making it good value for maintenance crews and industrial users who prioritize longevity and compatibility.

Frequently Asked Questions

Are these o-rings compatible with gasoline and diesel?
Yes, 434 Viton is formulated to resist petroleum products including gasoline and diesel, and the review source lists compatibility with fuel blends and biodiesel.

Do the rings meet standard AS568 sizes?
Yes, these rings are made to AS568 nominal sizing and include the actual dimensions for fit confirmation.

What is the usable temperature range?
The rated operating range is -26C (-15F) up to 232C (450F), suitable for many high-temperature and engine applications.