The GReddy Type-S Radiator Cap is a high-pressure cooling system upgrade designed to increase the boiling point of your engine coolant. By raising the relief valve pressure to 1.3 kg/cm², this cap allows the cooling system to operate more efficiently under high-load conditions, providing a vital margin of safety against overheating during spirited driving or track use.

• Pressure Rating: 1.3 kg/cm²
• Finish: Brushed aluminum with GReddy badge
• Construction: High-grade stainless steel components with heat-resistant silicone seals for consistent pressure management
• Fitment: Fits most Nissan, Subaru, Mazda, and Mitsubishi radiator necks, as well as select Toyota models

This Type-S cap replaces the factory low-pressure unit to ensure your cooling system remains pressurized and effective when temperatures rise. The brushed finish and GReddy branding provide a clean, performance-oriented aesthetic for any engine bay.

Fits select 2001-2024 GM Duramax and RAM 6.7L Cummins (2004.5-2007 & 2010-2024) equipped with WCFab fabricated coolant tanks.

The Wehrli Custom Fabrication (WCFab) Billet Coolant Tank Cap is a premium replacement designed for high-performance cooling systems. Precision-machined from billet aluminum and finished with a durable black anodized coating, this cap is engineered to match existing WCFab oil and brake reservoir caps for a cohesive look across your engine bay. Rated at 18-20 PSI, it ensures reliable pressure regulation for your fabricated coolant reservoir.

• Pressure Rating: 18-20 PSI
• Construction: CNC-machined billet aluminum
• Finish: Corrosion-resistant black anodized
• Compatibility: Exclusively for WCFab fabricated coolant tanks
• Matches WCFab billet oil and brake reservoir caps

The Koyorad SK-C13 Type A Hyper Radiator Cap is designed to improve cooling system performance by increasing the coolant boiling point. By maintaining a higher system pressure of 1.3 Bar (1.3 kg/cm²), this cap provides an additional margin of safety against boil-over during high-performance use or under extreme thermal loads.

• High Pressure Rating: 1.3 Bar (approx. 19 PSI) for increased heat capacity and boiling point.
• Deep Plunger Style: Specifically engineered for filler necks requiring the Type A deep plunger depth.
• Direct Fitment: Designed exclusively for Koyorad radiators equipped with Type A (Red Label) filler necks.
• Durable Construction: Features a high-quality valve and spring assembly to maintain consistent pressure under stress.
• Manufacturer Part Number: SK-C13

Fits select 2001-2024 Chevrolet and Dodge trucks equipped with WCFab fabricated coolant tanks (6.7L).

Upgrade your engine bay with the Wehrli Custom Fabrication (WCFab) Billet Aluminum Coolant Tank Cap. Engineered as a high-durability replacement for WCFab fabricated coolant tanks, this cap is CNC-machined from premium billet aluminum to withstand the heat and pressure of high-performance cooling systems. The clear anodized finish provides a clean, professional look while offering long-term protection against corrosion.

• Precision CNC-machined billet aluminum construction
• Clear anodized finish for corrosion resistance
• Pressure rated for 18-20 PSI systems
• Direct fit for WCFab fabricated coolant tanks
• Aesthetic match for WCFab oil and brake reservoir caps
• Manufacturer Part Number: WCF100472

Ensure a reliable seal on your custom cooling system with the Vibrant Performance Radiator Cap. Specifically engineered for precise compatibility with Vibrant Radiator Filler Necks, this cap provides the necessary pressure containment for high-performance automotive applications. It is an essential component for fabricators and builders finishing a custom radiator or header tank setup.

Constructed from high-grade 6061 aluminum, this radiator cap is CNC-machined for exact tolerances. The durable satin black finish provides a professional, understated aesthetic while protecting the aluminum against the harsh heat cycles of the engine bay. This cap is designed to install seamlessly onto matching filler necks, ensuring a leak-free interface.

• Material: 6061 Aluminum
• Finish: Satin Black
• Application: Fits Vibrant Performance Radiator Filler Necks
• Manufacturer Part Number: 20983

This Vibrant Performance radiator cap is precision-engineered to work specifically with Vibrant radiator filler necks. Machined from high-grade 6061 aluminum, it provides a durable and reliable seal for your cooling system while offering a clean, professional look in the engine bay.

Featuring a sleek satin black finish, this cap is designed for custom cooling system fabrication where performance and aesthetics are equally important. It replaces standard plastic or stamped steel caps with a robust, CNC-machined component.

• Constructed from premium 6061 aluminum for long-term durability
• Attractive satin black finish resists corrosion and heat
• Engineered specifically for compatibility with Vibrant Performance radiator filler necks
• Manufacturer Part Number: 20981

Fits select 1988-2001 Honda Civic, CRX, Prelude, and Acura Integra (1.5L / 1.6L / 1.8L / 2.2L / 2.3L).

Skunk2 High-Pressure Radiator Caps are engineered to optimize cooling system efficiency by increasing internal system pressure. This Type A cap features an open valve pressure of 1.3 kg/cm², which is approximately 0.2 kg/cm² higher than most factory OEM radiator caps. By increasing this pressure, the coolant boiling point is raised, providing a critical safety margin and more efficient heat dissipation under the high-load conditions of competitive racing or spirited street driving.

Designed as a functional engine bay upgrade, this cap is fully compatible with Skunk2 silicone radiator hoses and most high-performance aftermarket radiators. It replaces worn factory caps to ensure your cooling system maintains the pressure required for peak engine performance.

• Pressure Rating: 1.3 kg/cm² (18.5 psi)
• Manufacturer Part Number: 359-99-0020
• Elevates coolant boiling point for improved thermal management
• Fits most Mazda, Mitsubishi, Nissan, and Subaru applications
• Compatible with 1988-1991 Civic/CRX, 1990-1993 Integra, and 1992-2001 Prelude

Fits select 1990-2010 Honda and Acura models including Accord, Civic, Integra, RSX, TSX, Element, Fit, and S2000.

Skunk2 High-Pressure Radiator Caps are designed to improve cooling efficiency by increasing internal system pressure. By maintaining a higher pressure, the boiling point of your engine coolant is raised, providing a greater margin of safety against overheating and cavitation during high-load conditions on both the street and the track. Each cap is rated at 1.3 kg/cm², which is 0.2 kg/cm² higher than most factory equipment.

As part of Skunk2's Fine Tuning line, these Type B caps are a perfect finishing touch for a built engine bay and are specifically designed for use with Skunk2 silicone radiator hoses and factory-style radiator necks. This precision-engineered component replaces the standard OE cap to ensure your cooling system operates at its peak potential.

• Open Valve Pressure: 1.3 kg/cm² (18.5 psi)
• Fitment Type: Type B
• Manufacturer Part Number: 359-99-0010
• Increases coolant boiling point for improved heat dissipation
• Compatible with Skunk2 silicone radiator hoses

Increase your cooling system’s thermal ceiling with the Radium Engineering Type-A Radiator Cap. This high-pressure cap is rated at 1.5 bar (21.7 psi), which raises the boiling point of your engine coolant compared to standard 0.9 bar or 1.1 bar factory caps. This provides critical protection against boil-over during high-performance driving, track sessions, or in high-ambient temperature environments.

Designed for durability and precision, this cap ensures a consistent seal on the radiator neck to maintain system pressure. The sleek black finish provides a clean, professional look for any engine bay while the Type-A fitment is compatible with many aftermarket aluminum radiators and select OE applications.

• Pressure Rating: 1.5 Bar (21.7 PSI)
• Cap Style: Type-A
• Finish: Black
• Manufacturer Part Number: 18-0076-A15

The Radium Engineering Typ-A 1.3 Bar Radiator Cap is a high-performance cooling system upgrade designed to manage thermal loads more effectively. By increasing the cooling system's internal pressure to 1.3 bar (approximately 18.9 psi), this cap raises the boiling point of the coolant. This provides a critical safety margin during track sessions, high-ambient temperature driving, or high-load conditions where standard caps might allow for boiling or cavitation.

Constructed with a durable black finish, the Typ-A design is engineered to fit various aftermarket performance radiators and specific OEM cooling housings that utilize the common small Japanese-style radiator cap standard. This ensures a reliable seal and precise pressure relief for consistent cooling performance.

• Manufacturer Part Number: 18-0076-A13
• Pressure Rating: 1.3 Bar (18.9 psi)
• Cap Style: Typ-A (Small Japanese standard)
• Color: Black
• Function: Increases coolant boiling point for improved heat management

The Radium Engineering Type-A Radiator Cap is an essential cooling system upgrade designed to withstand the increased thermal demands of performance driving. With a 1.1 Bar (approximately 16 psi) pressure rating, this cap raises the boiling point of your engine coolant, providing a critical margin of safety against overheating and water pump cavitation during high-load scenarios.

This Type-A cap is engineered for a precise fit and reliable seal on compatible radiator necks, ensuring consistent system pressure. The sleek black finish provides a clean, professional look for any engine bay while replacing the standard factory cap with a higher-tolerance component.

• Manufacturer Part Number: 18-0076-A11
• Pressure Rating: 1.1 Bar (16 psi)
• Cap Configuration: Type-A
• Finish: Black
• Function: Increases coolant boiling point for improved thermal management

The Moroso High-Pressure Racing Radiator Cap is engineered to handle the extreme thermal demands of competitive racing. By maintaining a 34-38 PSI system pressure, this cap effectively raises the boiling point of your engine coolant, preventing boil-over and ensuring consistent cooling performance during high-load operation. It is a critical upgrade for cooling systems that need to perform beyond the limits of standard factory components.

• Pressure Rating: 34-38 PSI
• Manufacturer Part Number: 63333
• Optimized for high-performance and racing cooling systems
• Raised boiling point provides a greater safety margin against overheating
• Built to withstand the rigors of track use

The Moroso 63332 Racing Radiator Cap is engineered specifically for high-performance cooling systems that require elevated operating pressures. By maintaining a 31-33 lbs pressure range, this cap significantly raises the boiling point of the engine coolant, providing a critical margin of safety against overheating and fluid loss during demanding racing conditions.

• Manufacturer Part Number: 63332
• Pressure Rating: 31-33 lbs
• Application: Designed for professional racing and high-performance cooling systems
• Function: Increases cooling system efficiency by raising the coolant boiling point
• Compatibility: Fits standard large-size radiator necks

Maintain cooling system integrity under extreme track conditions with the Moroso 63324 Racing Radiator Cap. Specifically engineered for high-performance cooling systems, this high-pressure cap features a 23-25 lbs rating, which effectively raises the boiling point of your coolant to prevent boil-over and thermal expansion issues during racing.

Built to professional standards, this cap provides a consistent seal for your radiator or expansion tank, ensuring the cooling system remains pressurized to maximize heat transfer efficiency. It is a vital upgrade for high-horsepower applications where standard OE-pressure caps may allow premature venting and overheating.

• Manufacturer Part Number: 63324
• Pressure Rating: 23-25 lbs (psi)
• Application: High-performance and racing cooling systems
• Construction: Engineered for high-temperature durability and a precise fit
• Benefit: Increases coolant boiling point to prevent engine overheating

The Moroso 63320 Racing Radiator Cap is engineered for high-performance cooling systems that demand higher operating pressures than standard street applications. Rated at 19-21 lbs, this cap effectively raises the boiling point of your engine coolant, providing a vital margin of safety against overheating and boil-over during aggressive track use or high-RPM competition.

• Pressure Range: 19-21 psi (lbs)
• Manufacturer Part Number: 63320
• Function: Increases cooling system pressure to elevate the coolant boiling point
• Application: Designed specifically for racing and high-performance cooling configurations
• Reliability: Helps prevent coolant loss due to expansion under extreme heat conditions

Maintain consistent cooling system pressure under grueling track conditions with the Moroso Racing Radiator Cap. This high-pressure cap is engineered to raise the boiling point of your engine coolant, providing a critical safety margin when temperatures climb during competitive driving or high-load operation.

Designed to fit standard-size radiator filler necks, this cap features a calibrated 14-18 PSI pressure rating. The robust internal spring and high-temperature seal construction ensure reliable performance, preventing premature coolant discharge into the recovery tank and maintaining the thermal efficiency of your cooling loop.

• Pressure Rating: 14-18 lbs (PSI)
• Application: Racing and high-performance cooling systems
• Fitment: Standard size radiator filler necks
• Prevents premature boiling and coolant loss
• Manufacturer Part Number: 63316

Fits most import vehicles requiring a small-style radiator cap.

Optimizing a performance cooling system requires attention to the components that maintain system integrity under pressure. The Mishimoto High-Pressure 2.0 Bar Radiator Cap is engineered to withstand the increased thermal loads of high-performance driving. While factory caps are often rated for lower pressures, this 2.0 bar (28 psi) cap significantly raises the coolant boiling point, preventing fluid from prematurely escaping into the overflow reservoir and keeping it circulating within the engine block and radiator.

This small-style cap features an ergonomic design for easier grip during installation or removal. It serves as a durable replacement for standard small-profile caps that may fail under the high-pressure conditions found in modified or hard-driven vehicles.

• Pressure Rating: 2.0 bar (28 psi)
• Raises coolant boiling point for improved thermal efficiency
• Ergonomic design for easy installation and removal
• Fitment: Small-style radiator filler necks common on import vehicles
• Manufacturer Part Number: MMRC-20-SM

Maintain optimal cooling system pressure during high-performance driving with the Mishimoto 1.3 Bar High-Pressure Radiator Cap. Specifically designed for most domestic vehicles requiring a large-style cap, this component replaces factory caps that often vent prematurely under the stress of heavy loads or track conditions.

By increasing the system pressure to 1.3 Bar (19 psi), this cap effectively raises the boiling point of your engine coolant. This creates a more stable and efficient cooling system, keeping fluid inside the radiator rather than allowing it to leak into the overflow reservoir. Each cap features an ergonomic design to provide a better grip for installation and removal.

• Manufacturer Part Number: MMRC-13L
• Pressure Rating: 1.3 Bar (19 psi)
• Fitment: Fits most domestic vehicles with large-style radiator necks
• Function: Increases boiling point and prevents coolant loss to the overflow tank
• Design: Ergonomic shape for easier handling

Maintain optimal cooling system pressure and enhance engine bay aesthetics with the Mishimoto 1.3 Bar Carbon Fiber Radiator Cap. Designed specifically for small import vehicle fitments, this high-pressure cap is an essential upgrade for vehicles pushed to their limits on the track or during spirited street driving.

Standard OEM radiator caps are often unable to handle the increased pressure generated by high-performance cooling cycles, which can lead to coolant leaking into the overflow reservoir. By increasing the system pressure to 1.3 Bar (19 psi), this cap effectively raises the boiling point of your engine coolant, ensuring the system remains efficient and the fluid stays where it belongs—circulating through the engine and radiator.

This cap features a hand-laid carbon fiber exterior for a premium finish and an ergonomic design to facilitate easy installation and removal, even in tight engine bays.

• Pressure Rating: 1.3 Bar (19 psi)
• Material: Hand-laid carbon fiber exterior
• Fitment: Designed for most small import vehicles
• Function: Increases boiling point to improve cooling efficiency and prevent overflow
• Manufacturer Part Number: MMRC-13-SMCF

Fits most import vehicles equipped with a small, non-directional radiator filler neck. The Mishimoto High-Pressure 1.3 Bar Radiator Cap is engineered to maintain cooling system integrity during high-performance driving or heavy-load conditions.

Standard OE caps are often unequipped to handle the increased heat and pressure of a modified engine, leading to premature coolant discharge into the overflow reservoir. By increasing system pressure to 1.3 bar (19 psi), this cap effectively raises the boiling point of your coolant, providing a larger thermal margin and preventing boil-over. The integrated high-grade silicone gaskets offer superior durability and a more reliable seal than standard rubber, resisting cracking and heat-cycling degradation over time.

• Pressure Rating: 1.3 Bar (19 psi)
• Style: Small non-directional
• Gasket Material: High-temperature silicone for long-lasting seal
• Design: Ergonomic shape for simplified installation and removal
• Function: Raises coolant boiling point to improve cooling efficiency
• Manufacturer Part Number: MMRC-13-SMC

Designed for select import vehicles and aftermarket radiators requiring a small-style radiator cap, the Mishimoto MMRC-13-SM is an essential cooling system upgrade for high-performance applications.

During aggressive driving or track sessions, cooling system pressures can exceed the limits of a standard OE cap, leading to coolant loss through the overflow reservoir. This high-pressure radiator cap raises the boiling point of your engine coolant by increasing the system pressure to 1.3 bar (19 psi). By keeping the coolant under higher pressure, the system operates more efficiently and maintains thermal stability even under heavy load.

• Rated for 1.3 bar (19 psi) to increase boiling point and cooling efficiency
• Direct fit for most import vehicles and radiators requiring a small radiator cap
• Ergonomic design allows for easy installation and removal
• High-quality construction for reliable pressure management
• Part Number: MMRC-13-SM

Fits select 2002-2024 Subaru Baja, Crosstrek, Forester, Impreza, Legacy, Outback, WRX, and WRX STI. This radiator cap is a direct-fit performance upgrade for your Subaru cooling system, designed to handle the increased heat and pressure of demanding driving conditions.

The Mishimoto High-Pressure 1.3 Bar Radiator Cap replaces your factory cap to raise the boiling point of your engine coolant. By increasing the pressure at which the system releases fluid into the overflow reservoir, it maintains higher cooling efficiency during spirited driving or track use. This specific model features a one-way valve design to match the OEM functionality of your Subaru’s cooling system, ensuring proper coolant recovery and pressure regulation.

• Increased Pressure: Rated at 1.3 bar (19 psi) to raise the coolant boiling point for improved safety and efficiency.
• One-Way Functionality: Engineered to match the factory one-way valve design for reliable cooling system operation.
• Direct Fit: Precision small-style cap designed for a seamless installation on compatible Subaru radiator necks.
• Technical Detail: Includes a non-directional Mishimoto logo sticker to ensure a clean look regardless of final orientation.
• Manufacturer Part Number: MMRC-13-ONWY

Fits select 1991-2021 Ford, Lincoln, and Mercury vehicles including Crown Victoria, F-Series, and Town Car (3.0L).

Maintaining proper cooling system pressure is critical for engine longevity, especially during high-stress driving or towing. The Mishimoto 1.1 Bar Overflow Reservoir Cap is designed to replace aging or failing factory caps that often lose pressure over time. When a cap fails to maintain its rated pressure, it lowers the boiling point of your coolant, increasing the risk of overheating and system failure.

By maintaining a consistent 1.1 bar (16 psi), this cap raises the boiling point of your engine coolant, providing a safer and more efficient cooling system. The ergonomic design ensures easy installation and removal, making it a simple but vital upgrade for your cooling loop.

• Increased Boiling Point: 1.1 bar (16 psi) rating provides higher thermal headroom than worn OE caps.
• Direct Fit: Replaces the factory overflow reservoir cap on supported Ford, Lincoln, and Mercury models.
• Ergonomic Grip: Designed for easy removal and installation even in tight engine bays.
• Mishimoto Lifetime Warranty: Built to last and backed by a comprehensive limited lifetime warranty.

• Manufacturer Part Number: MMRC-11-FRD
• Pressure Rating: 1.1 Bar (16 psi)
• Fits Engines: 3.0L

Fits select 2013-2017 Scion FR-S, Subaru BRZ, and Toyota 86.

The Koyo Hyper Radiator Cap is an essential cooling system upgrade designed to handle the increased thermal demands of performance driving. This Blue Label version features a shallow plunger style, engineered to replace the factory cap and provide a more robust seal. By increasing the operating pressure of your cooling system, this cap raises the coolant boiling point, effectively increasing cooling efficiency and providing a vital safeguard against overheating during track sessions or spirited street use.

Constructed with high-quality components to ensure long-term durability under high-heat conditions, the SK-D13 Hyper Cap is a direct fit for the specified radiators, maintaining pressure consistency where standard OE caps may fail.

• Manufacturer Part Number: SK-D13
• Series: Hyper Radiator Cap (Blue Label)
• Style: Shallow Plunger
• Optimizes cooling system pressure for improved boiling point
• High-grade seals for heat resistance and durability

The HKS S-Type Radiator Cap is engineered to improve cooling system efficiency by increasing internal pressure. By raising the coolant boiling point, this high-pressure cap provides a vital safety margin against overheating during spirited driving or under high-load conditions. It is a direct replacement for the factory cap on vehicles utilizing an S-Type radiator neck.

• Increases cooling system pressure to enhance thermal management
• Raised boiling point prevents coolant vapor lock and overheating
• Manufactured with high-tension valve springs and heat-resistant silicone seals
• Engineered for precise pressure release and recovery
• Genuine HKS performance part; MPN: 15009-AK006

The HKS N-Type Radiator Cap is an essential cooling system upgrade for high-performance and track-oriented vehicles. Designed to maintain higher system pressure than standard factory caps, this component effectively raises the boiling point of your engine coolant. This increase in thermal headroom helps prevent coolant boil-over and reduces the risk of air pockets (cavitation) forming within the cooling passages during aggressive driving or high-heat conditions.

Built to HKS's rigorous standards, this cap features a high-grade seal to ensure reliable pressure retention and a precise fit. The N-Type configuration is a common fitment for various Japanese manufacturers; it serves as a direct-fit replacement for the original equipment cap to improve cooling efficiency and enhance engine bay aesthetics.

• Manufacturer Part Number: 15009-AK005
• Fitment Style: N-Type
• Function: Increases cooling system pressure to raise coolant boiling point
• Build: High-quality seals and spring for consistent pressure regulation
• Installation: Direct replacement for OE radiator cap

Enhance your engine bay aesthetics and cooling system reliability with the HKS Limited Edition "10" Radiator Cap. Specifically designed for the Hyundai Genesis Coupe, this performance radiator cap is engineered to maintain consistent system pressure, which helps raise the boiling point of your coolant and prevents overheating during spirited driving or track sessions.

As a direct replacement for the factory unit, this limited edition cap features the iconic HKS "10" branding, offering a unique look for collectors and enthusiasts. The high-pressure design ensures that the cooling system remains sealed and efficient under the increased thermal loads common in modified or hard-driven vehicles.

• Direct fit for Hyundai Genesis Coupe models
• Limited Edition "10" design logo and styling
• Constructed for durability and precise pressure management
• Helps prevent coolant boil-over and system cavitation
• Manufacturer Part Number: 15009-AK004

The GReddy Type-S Radiator Cap is a high-pressure cooling system upgrade designed to improve thermal efficiency and prevent overheating during high-performance driving. By increasing the valve opening pressure to 1.3 kg/cm² (127 kPa), this cap raises the boiling point of your engine coolant, providing a higher margin of safety under extreme engine loads.

Constructed with high-quality components and a durable spring mechanism, this cap ensures consistent pressure regulation. The polished finish provides a clean, professional look under the hood, making it an ideal choice for both track-focused builds and show cars. This Type-S model is designed to fit specific radiator neck styles common on many performance applications.

• Manufacturer Part Number: 13911004
• Pressure Rating: 1.3 kg/cm² (1.3 bar / 18.5 psi)
• Cap Style: Type-S
• Finish: Polished with GReddy badge
• Replaces factory low-pressure radiator caps

Fits select Honda and Toyota models equipped with the Type-N style radiator neck.

The GReddy Type-N 1.3 High-Pressure Radiator Cap is an essential cooling system upgrade for high-performance and track-driven vehicles. By increasing the radiator's internal pressure to 1.3 kg/cm² (1.3 bar or approximately 18.5 psi), this cap raises the boiling point of your engine coolant. This improved thermal threshold prevents coolant cavitation and helps maintain stable operating temperatures under heavy engine loads.

Manufactured from high-grade materials with a polished finish, the Type-N cap features a durable silicone seal to ensure a consistent, leak-free seat even under extreme heat cycling. It replaces the factory cap to provide both functional cooling benefits and a clean, show-quality aesthetic in the engine bay.

• Pressure Rating: 1.3 kg/cm² (18.5 psi)
• Neck Compatibility: Type-N style
• Material: Stainless steel body with high-temp silicone seal
• Finish: Polished with GReddy logo badge
• Manufacturer Part Number: 13911003

Fits select Nissan, Subaru, Mazda, Mitsubishi, and Toyota vehicles. The GReddy Type-S high-pressure radiator cap is a functional upgrade for your vehicle's cooling system, designed to increase the boiling point of the engine coolant. By raising the opening pressure to 1.3 kg/cm² (1.3 bar), this cap improves cooling efficiency and helps prevent overheating during spirited driving or track sessions.

Engineered for a precise seal, the Type-S cap replaces the factory unit and features a durable silicone seal and high-quality valve construction to ensure consistent pressure management under extreme thermal stress.

• Pressure Rating: 1.3 kg/cm² (1.3 bar)
• Fitment Style: Type-S (Small head)
• Finish: Black with GReddy logo plate
• Construction: High-grade materials with silicone seal
• Manufacturer Part Number: 13911002