Mr O-Ring 447 Viton O-Ring 90A Durometer 9in ID - Durable Seal

In this review the Mr O-Ring 447 Viton O-Ring is evaluated for use in demanding sealing jobs where chemical and temperature resistance matter most. The bottom line: this single-pack, 90A durometer Viton o-ring is aimed at technicians and maintenance professionals who need a compact, high-temperature resistant seal rated from -26C to 232C and compatible with petroleum fuels, diesel blends, mineral oils and many solvents. The review highlights real-world fit and material performance rather than marketing claims, and explains why the specific nominal and actual dimensions matter when replacing worn or degraded o-rings.

Key Features

• Material: Made from Viton (FKM) for excellent resistance to high temperature, ozone and many solvents, which reduces premature seal failure in harsh environments.
• Hardness: 90A durometer offers a firm cross-section that holds shape under compression and is suitable for static and some dynamic sealing tasks.
• Temperature range: Rated from -26C to 232C (-15F to 450F), making it suitable for applications exposed to very high air temperatures and hot fluids.
• Size accuracy: Nominal 9in ID and 9-1/2in OD with actual dimensions 8.975in ID and 9.525in OD, which helps ensure a proper fit when replacing AS568 sizes.
• Chemical compatibility: Performs well with petroleum products, fuels with methanol or ethanol blends, diesel, biodiesel blends, mineral and silicone oils, and many acids, extending service life in fuel and hydraulic systems.
• Shelf life: Effectively unlimited shelf life under proper storage, so spares can be kept without frequent replacement cycles.

Who It's For

This o-ring is best for industrial maintenance technicians, hydraulics and plumbing professionals, and equipment owners who need a reliable high-temperature seal that resists fuels, oils and many solvents. Its 90A durometer and Viton FKM formulation make it suitable for static sealing and many under-hood, fuel-handling or hot-fluid applications.

Those looking for very soft, low-durometer elastomers for delicate dynamic seals or for applications incompatible with fluorocarbon rubbers should consider alternative materials; likewise, shops that need multi-packs rather than single units may prefer other package sizes.

Pros & Cons

Pros

• High chemical and temperature resistance from the Viton compound helps prevent degradation in fuel and oil service.
• Precise actual dimensions make it easier to match replacements for AS568-aligned sizes.
• 90A durometer provides durability and shape retention under compression.
• Wide compatibility with oils, fuels and many solvents reduces the need for multiple seal materials.

Cons

• Single-pack format may be inconvenient for shops that prefer bulk quantities.
• 90A hardness is relatively firm and may not be ideal for every dynamic sealing application that needs a softer compound.

Specifications

Brand	Mr O-Ring
Material	Viton (FKM) 90A
Nominal dimensions	9in ID, 9-1/2in OD, 1/4in CS
Actual dimensions	8.975in ID, 9.525in OD, 0.275in CS
Metric dimensions	227.97 mm ID, 241.95 mm OD, 6.99 mm CS
Temperature range	-26C (-15F) to 232C (450F)

Our Verdict

The Mr O-Ring 447 Viton 90A o-ring is a sensible buy for anyone needing a compact, high-temperature and chemically resistant replacement seal that meets AS568 sizing expectations. It delivers good value for maintenance use where fuel, oil or high heat exposure would quickly degrade lesser elastomers, though buyers who need softer elastomers or bulk packaging should look elsewhere.

Frequently Asked Questions

Is this o-ring compatible with diesel and biodiesel blends?
Yes. The Viton formulation is listed as performing well with diesel and blends with biodiesel.

Can it handle high temperature air and hot fluids?
Yes. The rated range extends to 232C (450F), suitable for very high temperature air and many hot-fluid applications.

Are the supplied dimensions precise for replacement work?
Yes. The product provides both nominal and actual dimensions to help ensure correct fit when replacing AS568-size o-rings.