Mr O-Ring 429 Viton O-Ring 90A 5 in ID Pack of 5 - High Temp Seal

In this review the Mr O-Ring 429 Viton O-Ring 90A (pack of 5) is assessed for technicians, hobbyists and maintenance teams who need a durable, high-temperature seal. The bottom line: this set is best for sealing applications exposed to fuels, oils and elevated temperatures because the 90A Fluorocarbon (Viton) compound resists petroleum, biodiesel blends, silicone oils and many chemicals while remaining stable from -26C to 232C. For anyone replacing worn AS568-size o-rings or stocking a workshop, these rings are a reliable, ready-to-use option.

Key Features

• Material: 429 Viton (FKM) construction provides exceptional resistance to fuels, mineral oil and many organic solvents, reducing frequent replacements.
• Hardness: 90A durometer delivers a firm seal that holds shape under pressure while still allowing a compressible contact surface for leaks control.
• Nominal and actual size: Nominal 5 in ID with actual dimensions close to 4.975 in ID and 5.525 in OD for predictable fit in AS568-compliant grooves.
• Temperature range: Rated from -26C to 232C (-15F to 450F), making these o-rings suitable for high-temperature engines and industrial processes.
• Chemical compatibility: Performs well with petroleum products, methanol or ethanol blends, diesel or biodiesel blends, silicone oils and greases, increasing application versatility.
• Packaging: Sold as a pack of 5, which is convenient for routine maintenance or small projects where multiple replacements are required.

Who It's For

These Viton 90A o-rings are aimed at professionals and experienced DIYers who work on fuel systems, hydraulic fittings, pumps and high-temperature seals that encounter aggressive fluids. The combination of a firm 90A durometer and Viton chemical resistance is particularly useful where silicone or nitrile would degrade quickly.

Those who should look elsewhere include users needing very soft, flexible seals for low-pressure, low-temperature rubber-to-rubber applications or those requiring food-grade or potable-water certified elastomers, since this product is specified for industrial chemical and fuel resistance rather than food contact.

Pros & Cons

Pros

• Excellent chemical and high-temperature resistance from the Viton FKM compound.
• Accurate actual dimensions (4.975 in ID, 5.525 in OD) for reliable fit in standard AS568 size grooves.
• 90A durometer balances firmness and sealing ability for many industrial uses.
• Pack of 5 offers convenient spare parts for maintenance tasks.

Cons

• Not intended for food-grade or potable water applications where specific certifications are required.
• Higher durometer may be less suitable for very low-pressure or delicate sealing where a softer elastomer is preferred.

Specifications

Our Verdict

The Mr O-Ring 429 Viton 90A in the 5 in ID size is a practical choice for anyone needing durable, high-temperature and fuel-resistant seals. It offers accurate sizing to AS568 standards and a material profile suited to petroleum, biodiesel blends and many chemicals, making it good value for maintenance shops and technicians who prioritize longevity over lower-cost, less-resistant alternatives.

Frequently Asked Questions

Are these o-rings compatible with diesel and biodiesel blends?
Yes, Viton FKM is specified as compatible with diesel and blends with biodiesel and performs well in those fluids.

Do these rings meet AS568 size standards?
Yes, these Viton o-rings are offered to meet sizes defined by AS568 and list both nominal and actual dimensions for fit confirmation.

What temperature range will these withstand?
The rated operating range is -26C (-15F) to 232C (450F), suitable for high-temperature sealing applications.