Mr O-Ring 320 Viton O-Ring 90A 1-1/8in ID 1-1/2in OD - Pack of 25

In this review the Mr O-Ring 320 Viton O-Ring pack is assessed for technicians, hobbyists and maintenance professionals who need reliable seals for fuel, oil and high-temperature applications. The bottom line: this pack of 25 offers a durable, high-hardness Viton compound with a 90A durometer that stands up to heat, petroleum and many chemicals, making it a practical choice when material resistance and consistent sizing matter. If long service life in harsh environments is your priority, this review explains why these o-rings are worth considering.

Key Features

• Material: Made from Viton (fluorocarbon rubber), these o-rings deliver excellent resistance to fuels, mineral oils and many organic solvents, which reduces frequent replacement in harsh fluids.
• Durometer: The 90A hardness provides a firm seal that resists extrusion and deformation, useful where a tighter, more durable seal is required under pressure.
• Temperature range: Rated from -26C to 232C (-15F to 450F), they tolerate very high operating temperatures and remain useful across wide environmental conditions.
• Size accuracy: Nominal and actual dimensions are provided (nominal 1-1/8in ID, 1-1/2in OD; actual 1.100in ID, 1.520in OD), helping installers match existing grooves and avoid fitment surprises.
• Pack size: Supplied as a pack of 25, this quantity is convenient for repeat maintenance tasks or stocking common service items without buying single units repeatedly.

Who It's For

This product suits industrial maintenance crews, small engine mechanics and plumbing professionals who need o-rings that resist petroleum, diesel blends, hydraulic fluids and elevated temperatures. The 90A hardness and Viton compound are particularly appropriate where chemical resistance and reduced swelling are required.

Those who should look elsewhere include applications requiring very soft seals (lower durometer) or food- or medical-grade elastomers, since Viton 90A is optimized for chemical and temperature performance rather than ultra-soft sealing or regulated sanitary uses.

Pros & Cons

Pros

• High chemical and heat resistance from the Viton material reduces degradation in harsh fluids.
• 90A durometer offers reliable firmness and durability under compression and repeated cycles.
• Pack of 25 gives good value for routine maintenance and multiple repairs.
• Actual and metric dimensions are listed for accurate compatibility checks.

Cons

• Higher durometer means less flexibility for applications that need a very soft, conforming seal.

Specifications

Brand	Mr O-Ring
Material	Viton (FKM)
Durometer	90A
Nominal dimensions	1-1/8in ID, 1-1/2in OD, 3/16in CS
Actual dimensions	1.100in ID, 1.520in OD, 0.210in CS
Metric dimensions	27.94 mm ID, 38.60 mm OD, 5.33 mm CS
Temperature range	-26C to 232C (-15F to 450F)

Our Verdict

The Mr O-Ring 320 Viton 90A pack is a sensible buy for professionals who need chemically resistant, high-temperature o-rings in a reliable size and quantity. Its combination of Viton material, clear actual dimensions and a useful pack size make it good value for industrial and automotive maintenance where durability matters.

Frequently Asked Questions

Are these o-rings suitable for fuel systems?
Yes. The Viton compound is formulated to perform well with petroleum, fuel blends and diesel applications that require chemical resistance.

Will the 90A hardness seal under high pressure?
The 90A durometer offers a firmer seal that resists extrusion; it is suitable for many pressurized seals but confirm groove clearance and application specifics before use.

What temperature range can these o-rings handle?
They are rated from -26C (-15F) to 232C (450F), making them appropriate for very high temperature exposure typical in engines and industrial equipment.