Nuke Performance Type-A Radiator Caps

Nuke Performance Type-A "Mini" Radiator Caps are designed for demanding street, track, and motorsport cooling systems using 32mm Type-A radiator necks. Available in 1.1, 1.3, 1.5, and 2.0 BAR pressure ratings, these precision-calibrated radiator caps help maintain consistent cooling-system pressure, increase coolant boiling margins, and improve thermal stability under high-load conditions.

Key Features

• Type-A "Mini" radiator caps designed for 32mm radiator necks
• Available in 1.1, 1.3, 1.5, and 2.0 BAR pressure ratings
• Pressure ratings from 16.0 PSI to 29.0 PSI
• Fits all Nuke Performance Coolant Expansion Tanks
• Compatible with a wide range of OEM applications
• Suitable for custom cooling-system installations
• Stainless steel valve and cap construction
• Durable silicone sealing material
• Silicone sealing provides superior durability compared with conventional natural-rubber OEM seals
• Designed for consistent pressure control
• Suitable for street, track, and motorsport applications

Fitment / Application

Nuke Performance Type-A Radiator Caps are designed for 32mm radiator necks using the Type-A seal configuration. They fit all Nuke Performance Coolant Expansion Tanks and are also compatible with a wide range of OEM and custom cooling-system applications equipped with a matching 32mm Type-A radiator neck.

The caps are widely used across Japanese performance platforms, including Honda B-, K-, and H-series engines; Nissan SR, RB, and VR engines; Toyota Celica, MR2, 1JZ, and 2JZ applications; Subaru EJ engines; Mazda rotary engines and MX-5 applications; and Mitsubishi 4G63 engines.

They are also compatible with select European vehicles and motorsport builds equipped with a Type-A 32mm radiator neck.

Important: Always verify the radiator neck type and dimensions before installation. The pressure rating should also be selected according to the requirements and limitations of the complete cooling system.

Available Pressure Ratings

Nuke Performance Type-A Radiator Caps are available in four pressure ratings:

• 1.1 BAR (16.0 PSI) – Part #452-01-011
• 1.3 BAR (18.9 PSI) – Part #452-01-013
• 1.5 BAR (21.8 PSI) – Part #452-01-015
• 2.0 BAR (29.0 PSI) – Part #452-01-020

The stated pressure rating represents the nominal release pressure and operates within a defined tolerance range. Each cap is precision-calibrated for consistent pressure control.

Stainless Steel Construction and Silicone Sealing

The Nuke Performance Type-A Radiator Caps feature stainless steel valve and cap construction for long-lasting durability in demanding cooling-system environments.

The sealing element uses silicone rather than the natural rubber commonly found in OEM radiator caps. This provides enhanced durability and longevity while maintaining a reliable seal during repeated exposure to heat and cooling-system pressure.

Radiator Cap Pressure and Coolant Boiling Point

Cooling-system pressure directly affects the boiling point of coolant. Increasing system pressure raises the coolant boiling point, providing a greater boiling margin and helping reduce the risk of localized boiling under high thermal loads.

Approximate boiling points are:

Approximate values. Actual boiling point varies depending on coolant formulation and cooling-system conditions. Cap ratings are gauge pressure.

Higher system pressure can increase the coolant boiling point, reduce the risk of localized vapor formation, and improve thermal stability during high-load operation. However, increased pressure also places greater stress on cooling-system components, including hoses, radiators, expansion tanks, and seals.

For this reason, always select the lowest pressure radiator cap that provides sufficient boiling margin for your application.

Why Radiator Cap Pressure Matters for High-Performance Engines

High-performance and turbocharged engines can expose the cooling system to extreme cylinder pressures, elevated exhaust gas temperatures, and sustained thermal loads. Even when the average coolant temperature appears stable, localized areas inside the cylinder head can experience substantially higher temperatures.

When coolant reaches its local boiling point, micro-boiling can occur. Vapor pockets transfer heat much less effectively than liquid coolant, potentially reducing local heat-transfer efficiency and increasing component temperatures.

Selecting an appropriately rated radiator cap increases cooling-system pressure and raises the coolant boiling point. This can help stabilize coolant behavior and cooling performance during high-load operation.

Nuke Performance Type-A Radiator Caps are engineered for precise pressure control and reliable operation in performance street vehicles, track applications, and demanding motorsport environments.

Nuke Performance Type-A Radiator Caps Specifications

Fitment Guide

Nuke Performance Type-A Radiator Caps fit all Nuke Performance Coolant Expansion Tanks and are widely used on Japanese performance engine platforms equipped with the appropriate 32mm Type-A radiator neck.

The caps are also compatible with select European vehicles and motorsport applications equipped with a Type-A 32mm radiator neck. Always verify the radiator neck specification before installation.

Part Numbers

• 452-01-011 – Type-A Radiator Cap, 1.1 BAR (16.0 PSI)
• 452-01-013 – Type-A Radiator Cap, 1.3 BAR (18.9 PSI)
• 452-01-015 – Type-A Radiator Cap, 1.5 BAR (21.8 PSI)
• 452-01-020 – Type-A Radiator Cap, 2.0 BAR (29.0 PSI)

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