Mr O-Ring 432 Viton O-Ring 90A Durometer - Pack of 5

In this review the focus is on the Mr O-Ring 432 Viton O-Ring, a 90A durometer seal sold in a pack of five that is targeted at technicians, maintenance teams and DIYers who need a resilient seal for fuel, oil, chemical and high-temperature applications. The bottom line: this o-ring stands out for its temperature and chemical resistance, making it a reliable replacement part for pumps, fittings and static sealing tasks where compatibility with petroleum products and elevated temperatures is required. The review highlights durability, measured dimensions and practical uses.

Key Features

• Material: Viton fluorocarbon rubber provides excellent resistance to fuels, mineral oils and many solvents so it holds up in harsh chemical environments.
• Temperature range: Rated from -26C to 232C, the o-ring remains flexible in cold service and stable at very high temperatures for engine and industrial use.
• Hardness: 90A durometer gives a firmer seal preferred in pressurized or static oil and fuel applications where extrusion resistance matters.
• Pack quantity: Supplied as a pack of five which is convenient for small maintenance jobs or keeping a reliable spare on hand.
• Standards and fit: Sized to AS568 nominal dimensions with actual measurements provided so installers can match the part with confidence for common sealing grooves.
• Chemical versatility: Performs well with petroleum, diesel, biodiesel blends, methanol or ethanol blends, silicone oils and high vacuum service for broad compatibility.

Who It's For

This o-ring is aimed at professionals and experienced hobbyists who repair or maintain engines, pumps, hydraulic fixtures and plumbing that encounter fuels, oils, solvents or elevated temperatures. It is also suitable for laboratory or industrial equipment requiring a compact, high-temperature resistant fluorocarbon seal.

Those who should look elsewhere include users who need a very soft seal for low-pressure water-only plumbing or those requiring FDA food-grade elastomers; Viton excels in chemical and temperature resistance but is not the ideal choice for all potable water or food-contact applications.

Pros & Cons

Pros

• High chemical and fuel resistance makes it dependable in petroleum and solvent environments.
• Wide temperature capability from -26C to 232C supports diverse industrial and automotive uses.
• 90A durometer balances firmness and resilience for durable sealing under pressure and repeated service.
• Pack of five offers multiple replacements or spares for routine maintenance.

Cons

• Viton is not the preferred material for food-grade or pure water applications, limiting use in potable systems.
• The firmer 90A hardness may be less suitable for very low-pressure or delicate sealing surfaces that need softer compression.

Specifications

Material	Viton (FKM)
Durometer	90A
Nominal dimensions	5-3/8 in ID, 5-7/8 in OD, 1/4 in CS
Actual dimensions	5.350 in ID, 5.900 in OD, 0.275 in CS
Metric dimensions	135.89 mm ID, 149.87 mm OD, 6.99 mm CS
Temperature range	-26C (-15F) to 232C (450F)
Pack quantity	Pack of 5

Our Verdict

The Mr O-Ring 432 Viton 90A pack delivers solid value for anyone needing a chemically resistant, high-temperature o-ring in a common AS568 size. Its measured actual dimensions and broad compatibility with fuels and oils make it a dependable replacement part for industrial maintenance and automotive repairs, though those requiring food-grade or very soft seals should consider alternate elastomers.

Frequently Asked Questions

Is this o-ring compatible with gasoline and diesel?
Yes. The Viton material is formulated to resist petroleum products, diesel and biodiesel blends, making it suitable for fuel system seals.

Will it handle continuous high temperatures?
Yes. The rated temperature range up to 232C (450F) supports many continuous high-temperature applications, though exact service life depends on operating conditions.

Are these rings sized to standard AS568 dimensions?
Yes. The product is offered to AS568 nominal dimensions and actual measurements are provided for accurate fitting.