Ishino Spark Plug Tube Seal

Ishino Stone Spark Plug Tube Seals: OEM Precision from a Century-Old Manufacturer

When it comes to keeping oil out of spark plug wells and maintaining a clean, efficient ignition system, the spark plug tube seal is a small but critical component. Ishino — operating under its well-known Stone gasket brand — brings a century of sealing expertise to this specific application, making it a go-to choice for owners of Japanese and Korean vehicles who demand factory-grade reliability.

A Legacy Built on Sealing Excellence

Founded in 1923 and headquartered in Tokyo, Ishino (formally Corteco Ishino Corporation) has grown into one of the most trusted names in OEM-grade engine sealing. The company operates manufacturing facilities in Japan and Singapore and has spent decades as a tier-1 OEM supplier to Toyota, Honda, and other major Japanese automakers. That direct OEM relationship is exactly why Ishino's aftermarket parts carry so much credibility — the engineering knowledge behind every seal comes straight from the factory floor.

Why Ishino Spark Plug Tube Seals Stand Out

Ishino markets its gaskets and seals under two distinct sub-brands: Stone (gaskets and formed seals) and TKK (oil seals). Their spark plug tube seals fall under the Stone lineup and are engineered to match OEM dimensions and material specifications precisely. Key attributes include:

• OEM-spec construction: Every product is manufactured to the same specification as the original equipment, ensuring a proper drop-in fit without modification.
• Premium rubber materials: Ishino spark plug tube seals are produced from high-grade elastomers selected to withstand the heat cycling and chemical exposure found inside a modern cylinder head.
• Broad vehicle coverage: The current lineup covers applications spanning Toyota, Honda, Subaru, Mitsubishi, Infiniti/Nissan, and other Japanese and Korean platforms — from the Eagle Talon and Mitsubishi Eclipse to the Infiniti G37.
• Precision manufacturing process: Ishino employs a "superb quality and precision manufacturing process" to ensure consistent sealing dependability across the entire product range.
• 24-Month / 24,000-Mile Warranty: Ishino backs its spark plug tube seals with a warranty covering defects in materials and workmanship, giving DIYers and professional installers alike added confidence.

When and Why to Replace Your Spark Plug Tube Seal

On many overhead-cam engines — particularly those from Honda, Toyota, and Subaru — the spark plug tubes pass through the valve cover into the cylinder head. The rubber seal around each tube prevents oil from migrating down into the plug well. When these seals harden, crack, or shrink with age, oil contamination of the spark plug well can cause misfires, premature plug fouling, and potentially damage ignition coil boots. Replacing the spark plug tube seal during a valve cover gasket service is considered best practice, and using an OEM-equivalent seal like Ishino Stone ensures the repair lasts.

With eight fitment-specific part numbers in stock, Ishino's spark plug tube seal selection offers targeted coverage for the vehicles that most commonly need this repair. Whether you are performing a routine tune-up or a more involved top-end refresh, Ishino Stone delivers the factory-matched quality that enthusiasts and professional technicians have trusted for generations.