Mr O-Ring 433 Viton O-Ring 90A Durometer 5-1/2in ID Pack of 5

In this review the Mr O-Ring 433 Viton o-ring is evaluated for workshop and industrial sealing tasks where temperature resistance and chemical compatibility matter most. The bottom line: this pack of five 90A durometer Viton o-rings is best for technicians and DIYers who need durable seals that resist fuels, oils and high temperatures; the single biggest reason to buy is the combination of a high-performance FKM compound and accurate dimensions that fit AS568 sizing standards.

Key Features

• Material: Viton (FKM) provides excellent resistance to fuels, mineral oils, hydraulic fluids and many organic solvents for long-lasting seals.
• Durometer: The 90A hardness offers a firm cross-section that holds shape under compression and performs well across a wide temperature range.
• Temperature range: Rated from -26C (-15F) to 232C (450F), allowing use in high-temperature air or fluid environments without rapid degradation.
• Dimensions: Nominal 5-1/2in ID, 6in OD and 1/4in cross-section with actual measured dimensions close to spec for reliable fitment in standard AS568 grooves.
• Chemical compatibility: Performs well with petroleum products, methanol/ethanol blends, diesel/biodiesel, silicone greases and many acids for broad application use.
• Pack size: Supplied as a pack of five so small maintenance jobs or multiple assemblies can be completed without ordering single pieces.

Who It's For

The 433 Viton o-ring is aimed at mechanics, maintenance technicians and hobbyists who need a small set of robust seals for fuel systems, hydraulic lines, pumps or other equipment exposed to oils and high temperatures. Its 90A hardness and FKM chemistry suit applications where a firmer seal is preferred and chemical resistance is required.

Those who need extremely soft, low-pressure seals or specialized elastomers for very low-temperature service should look elsewhere; silicone or nitrile compounds with different durometers are better choices for soft sealing or cryogenic conditions.

Pros & Cons

Pros

• High chemical resistance from Viton means longevity in fuel and oil applications.
• Wide operating temperature range supports both elevated heat and moderately cold environments.
• Accurate actual dimensions (5.475in ID, 6.025in OD, 0.275in CS) make installation predictable in AS568 sized grooves.
• Pack of five is convenient for repairs and spares without excess waste.

Cons

• 90A hardness is relatively firm and may not seal as well in very low-pressure or delicate interfaces compared with softer o-rings.

Specifications

Material	Viton (FKM)
Durometer	90A
Nominal ID	5-1/2 in
Actual ID	5.475 in (139.07 mm)
Nominal OD	6 in
Actual OD	6.025 in (153.05 mm)
Cross-section	1/4 in (0.275 in actual, 6.99 mm)
Temperature range	-26C (-15F) to 232C (450F)

Our Verdict

The Mr O-Ring 433 Viton 90A pack of five is a practical choice for professionals and home mechanics who need chemically resistant, heat-tolerant seals in standard AS568 sizes. Its accurate dimensions and robust FKM compound deliver reliable performance and good value for maintenance and repair tasks where durability matters most.

Frequently Asked Questions

Can these o-rings handle fuel and oil exposure?
Yes, Viton (FKM) is specifically resistant to petroleum products, diesel blends and many mineral oils, making these o-rings suitable for fuel and oil-exposed seals.

Will the 90A hardness work for my application?
The 90A durometer is relatively firm and is ideal for applications requiring shape retention and high-temperature stability; choose a softer compound if you need low-pressure conforming seals.

Are the dimensions reliable for standard replacement?
Yes, the product lists both nominal and actual dimensions that align with AS568 sizing, so these should fit standard grooves specified for a 5-1/2in ID / 6in OD o-ring.