Mr O-Ring 237 Viton O-Ring 90A Durometer, 3-3/8in ID (Pack of 25)

In this review the Mr O-Ring 237 Viton O-Ring is evaluated for mechanics, HVAC technicians and maintenance buyers who need reliable chemical and temperature resistance in a standard AS568 size. The bottom line: these 90A durometer Viton o-rings deliver dependable sealing where fuel, oil, solvent or high heat exposure is expected, and the pack of 25 makes them economical for routine maintenance. The reviewer found the material properties and dimensional consistency make this kit a practical choice when compatibility with petroleum, diesel blends, and high temperature air is required.

Key Features

• Material: Made from Viton (fluorocarbon rubber), offering strong resistance to fuels, oils and many organic solvents for longer service life.
• Durometer: 90A hardness provides a firm seal that resists extrusion and maintains shape under compression in demanding applications.
• Temperature range: Rated from -26C to 232C (-15F to 450F), useful for both cold starts and very high temperature environments.
• Pack size: Supplied as a pack of 25, which reduces downtime and cost for shops that change multiple seals during routine servicing.
• Dimensional accuracy: Nominal and actual dimensions are closely matched, easing replacement with existing AS568 sizes without custom fitting.
• Versatility: Performs well in contact with fuels, biodiesel blends, silicone oils, and under ozone and weather exposure, so it fits diverse sealing needs.

Who It's For

These o-rings are best suited to technicians and maintenance buyers working with fuel systems, hydraulic lines, pumps or high temperature equipment where resistance to petroleum, biodiesel blends and solvents is required. The pack size and rugged 90A durometer make them practical for workshops and field service teams replacing multiple seals in a single job.

Users who need extremely soft or flexible seals for low-pressure or delicate applications should look at lower durometer materials, and those requiring FDA-grade or food-contact certification should confirm compatibility with their specific regulatory needs before purchase.

Pros & Cons

Pros

• Excellent chemical and high temperature resistance from the Viton formulation ensures long service life in harsh environments.
• Pack of 25 offers good value and reduces repeat orders for maintenance teams.
• Accurate actual dimensions mean straightforward replacement for AS568 size matches.

Cons

• 90A hardness is relatively firm, which may not seal as well in very low-pressure or highly irregular grooves compared with softer materials.

Specifications

Our Verdict

The Mr O-Ring 237 Viton o-ring pack is a solid, cost-effective choice for professionals who need durable seals resistant to fuels, oils and high heat. Its accurate sizing, broad chemical compatibility and 90A hardness make it good value for maintenance shops and field technicians, while those needing softer sealing materials or specific food-grade certification should consider alternatives.

Frequently Asked Questions

Are these o-rings compatible with diesel and biodiesel blends?
Yes; the Viton compound is described as performing well with diesel and blends with biodiesel.

Do the dimensions match AS568 sizing?
Yes; the product is intended to meet size standards defined by AS568 and lists both nominal and actual dimensions for confirmation.

What temperature range will these o-rings handle?
They are rated for -26C (-15F) up to 232C (450F), suitable for many high temperature sealing applications.