Maintain reliable engine sealing and prevent unwanted coolant leaks with the Genuine Honda Engine Coolant Pipe O-Ring (91311-PRB-A00). This factory replacement O-ring is designed to provide a secure, leak-resistant seal at designated coolant pipe connections on compatible Honda and Acura K-Series engines.

Manufactured to Honda's original equipment specifications, this precision-engineered O-ring measures 13.5mm x 3.5mm and is designed to maintain a dependable seal between mating cooling system components.

Proper cooling system sealing is essential for maintaining coolant levels, regulating engine operating temperatures, and preventing overheating. Over time, exposure to engine heat, coolant, and repeated temperature changes can cause rubber O-rings to harden, flatten, crack, or lose their original elasticity.

Whether you're repairing a coolant leak, servicing your engine's cooling system, or completing a K20 or K24 engine rebuild, the Genuine Honda 91311-PRB-A00 O-ring provides the factory-quality fitment and reliability needed for long-term performance.

Features

• Genuine Honda OEM Part: Manufactured to Honda's original factory specifications for dependable fitment and sealing performance.

• Precision Dimensions: Features a nominal 13.5mm x 3.5mm size for applications requiring this specific O-ring.

• Reliable Coolant Sealing: Helps prevent coolant leakage at compatible engine coolant pipe connections.

• Heat-Resistant Construction: Designed to withstand normal engine operating temperatures and repeated heating and cooling cycles.

• Coolant-Resistant Material: Engineered for use in compatible automotive cooling system applications.

• Direct OEM Replacement: Replaces the original factory O-ring without modifications when used in the correct application.

• Precision-Molded Design: Provides a consistent sealing profile for proper installation.

• Supports Cooling System Reliability: Helps maintain proper coolant containment and cooling system operation.

• Ideal for Engine Maintenance: Recommended when servicing coolant pipes or related components that use this seal.

• Factory-Quality Replacement: Suitable for OEM restoration, preventative maintenance, and performance engine builds.

Additional Information

Manufacturer: Honda Motor Co., Ltd.

Brand: Genuine Honda OEM

Honda Part Number: 91311-PRB-A00

Product Name: Engine Coolant Pipe O-Ring

OEM Description: O-Ring (13.5 x 3.5)

Alternative Names: Coolant Pipe Seal, Water Pipe O-Ring, Engine Cooling System O-Ring

Component Type: Engine Sealing O-Ring

Nominal Dimensions: 13.5mm x 3.5mm

Material: OEM elastomer; exact compound not specified

Installation Location: Application-dependent engine sealing connection

Primary Engine Family: Honda K-Series

Fitment Type: Direct OEM Replacement

Condition: New

Quantity: Sold Individually

Additional Notes: Honda also catalogs this O-ring in the cylinder block and oil pan assembly on certain K-Series applications. Always consult the correct OEM parts diagram to identify its installation location and confirm whether the serviced joint contains coolant or engine oil.

Common Reasons for Replacement

• Coolant Leaks: A deteriorated O-ring at a coolant pipe connection can allow coolant to escape from the cooling system.

• Aging Rubber Seals: Prolonged exposure to heat and temperature fluctuations can cause O-rings to harden or lose elasticity.

• Cooling System Repairs: Replacing disturbed seals helps prevent leaks after removing and reinstalling coolant pipes.

• Engine Rebuilds: Installing fresh OEM sealing components is recommended when reassembling an engine.

• Component Removal: O-rings can become stretched, pinched, or damaged during disassembly.

• Preventative Maintenance: Replacing older seals during major engine service can help avoid future leaks.

• Damaged or Flattened Seals: Cuts, cracks, deformation, or excessive compression can prevent an O-ring from sealing properly.

Installation Notes

1. Verify Compatibility: Confirm that Honda part number 91311-PRB-A00 is specified for your engine and the exact sealing location being serviced.

2. Allow the Engine to Cool: Never open or disassemble a pressurized cooling system while the engine is hot.

3. Prepare the Vehicle: Disconnect the negative battery terminal when required by the service procedure and gain access to the applicable component.

4. Drain Fluids as Necessary: If servicing a coolant connection, drain the cooling system to the appropriate level. Follow the factory procedure for other installation locations.

5. Remove the Existing O-Ring: Carefully remove the original seal without scratching the surrounding metal surfaces or damaging the O-ring groove.

6. Inspect the Sealing Surfaces: Check the mating components for corrosion, debris, cracks, scratches, or other damage that could compromise sealing performance.

7. Clean the Components: Remove dirt, deposits, and old sealing material using cleaning methods approved for the component being serviced.

8. Install the New O-Ring: Apply the lubricant specified by the Honda service manual and position the new seal evenly in its designated groove without twisting or pinching it.

9. Reassemble the Components: Reinstall the removed components using the correct Honda torque specifications and installation procedures.

10. Refill and Inspect: If the cooling system was opened, refill it with the specified coolant, bleed trapped air according to Honda's procedure, and inspect the repaired connection for leaks.

Installation Recommendation: Replace any O-ring that is cracked, flattened, cut, or otherwise damaged. Proper sealing surface preparation and correct installation are essential for reliable operation.

What's Included

• (1) Genuine Honda O-Ring (13.5 x 3.5mm) – Part Number 91311-PRB-A00

Note: This product includes one individual O-ring. Coolant pipes, hoses, fittings, additional seals, and installation hardware are sold separately unless otherwise specified.

The Genuine Honda O-Ring (91311-PRB-A00) is an essential OEM replacement component for maintaining dependable sealing performance on compatible Honda and Acura K-Series engines. Featuring precise 13.5mm x 3.5mm dimensions and factory-quality construction, this O-ring is an excellent choice for cooling system repairs, engine maintenance, and complete K-Series rebuilds.

Whether you're restoring a factory K20 engine, servicing your Acura TSX, or assembling a high-performance K20/K24 build, choosing genuine Honda sealing components helps ensure proper fitment and long-term reliability.