233 Viton O-Ring 90A Durometer, 2-7/8 in ID - Pack of 25

In this review the reviewer evaluates the Mr O-Ring 233 Viton O-ring pack and finds it best suited for technicians and maintenance professionals who need reliable chemical and high-temperature sealing. The bottom line: these 90A durometer Viton rings combine a wide usable temperature range and strong resistance to fuels and oils, making them a solid choice for demanding sealing tasks. The pack of 25 provides parts room or job-site spares, and the review focuses on durability, dimensional accuracy and material performance in petroleum and high-temperature environments.

Key Features

• Material: Fluorocarbon rubber (Viton/FKM) offers excellent resistance to fuels, oils, aromatics and many organic solvents which reduces seal failures in chemical exposure.
• Durometer: 90A hardness provides a firm cross-section that holds shape under compression and is suitable where a stiffer seal is preferred.
• Temperature range: Rated from -26C to 232C (-15F to 450F), allowing use in high-temperature engine, industrial and process applications without rapid degradation.
• Size accuracy: Nominal and actual dimensions are provided (2-7/8 in ID nominal, actual 2.859 in ID) which helps installers choose compatible shafts and grooves with confidence.
• Pack quantity: Twenty-five rings in black supply spares for multiple repairs or for keeping a stock of commonly used sizes on hand.
• Versatility: Performs well with petroleum products, diesel blends, mineral and silicone oils, and holds up to ozone, weather and high vacuum conditions.

Who It's For

This product is aimed at professional mechanics, maintenance technicians and industrial users who need a robust sealing material resistant to fuels, oils and high temperatures. The 90A hardness makes these O-rings appropriate for static and some dynamic seals where a firmer profile is required and where chemical exposure is likely.

Hobbyists or applications requiring very soft sealing, extreme low-temperature flexibility below -26C, or food-grade elastomers should look elsewhere, since Viton FKM is optimized for chemical and heat resistance rather than ultra-low temperature flexibility or food-contact certification.

Pros & Cons

Pros

• Excellent chemical resistance to fuels, oils and many organic solvents, reducing seal failures in exposed systems.
• High temperature capability to 232C (450F) for use in engine and industrial applications.
• Accurate listed actual dimensions (2.859 in ID, 3.137 in OD, 0.139 in CS) simplify replacement and groove matching.
• Pack of 25 provides good value for maintenance stocking and repeat repairs.

Cons

• 90A durometer is relatively firm and may not be ideal where a softer, low-pressure seal is needed.
• Not intended for food-grade or extreme cold applications below the stated temperature range.

Specifications

Brand	Mr O-Ring
Material	Viton (Fluorocarbon rubber, FKM)
Durometer	90A
Nominal dimensions	2-7/8 in ID, 3-1/8 in OD, 1/8 in CS
Actual dimensions	2.859 in ID, 3.137 in OD, 0.139 in CS
Metric dimensions	72.62 mm ID, 79.68 mm OD, 3.53 mm CS
Temperature range	-26C (-15F) to 232C (450F)

Our Verdict

The Mr O-Ring 233 Viton O-ring pack is a practical choice for professionals who need durable, chemically resistant seals with reliable dimensional accuracy. For applications involving petroleum products, high heat or ozone exposure, these 90A Viton rings deliver strong value, and the pack size keeps spares on hand for ongoing maintenance needs.

Frequently Asked Questions

Are these O-rings suitable for fuel systems?
Yes. Viton FKM is formulated to resist petroleum, gasoline and diesel blends and is suitable for many fuel-system seals.

What is the effective temperature range?
The specified range is -26C (-15F) up to 232C (450F), which covers most engine and industrial thermal conditions.

How accurate are the listed sizes?
The listing includes both nominal and actual dimensions (2.859 in ID, 3.137 in OD, 0.139 in CS) to help ensure proper fit when replacing or stocking seals.