Moroso Racing Radiator Cap 16 lb, stainless steel spring & brass retainer

Moroso 63316 is a 16 lb racing radiator cap engineered to hold a precise pressure with a stainless steel spring and a solid brass spring retainer for standard-size filler necks.

This radiator cap is built for high-performance cooling systems that need a dependable pressure setting. Made in the United States, the 63316 fits standard-size radiator filler necks and uses a corrosion-resistant stainless steel spring combined with a solid brass retainer to keep the pressure constant under demanding conditions. It’s available in a range of pressure ratings; this specific SKU is rated at 16 pounds to help control boilover and maintain system pressure typical in racing and performance driving.

How does this radiator cap control cooling system pressure?

The cap contains a calibrated stainless steel spring that compresses at a set pressure, allowing excess coolant vapor to escape to the overflow when the system reaches that threshold. When temperature and pressure drop, the spring reseats to restore system seal and maintain the designed pressure level. Reliable mechanical parts reduce gradual pressure drift over time that can occur with lower-quality caps.

• Calibrated stainless steel spring holds 16 lb pressure.
• Solid brass spring retainer prevents loosening under heat.
• Designed for standard-size filler necks for straightforward fitment.

Will the Moroso 63316 fit my vehicle?

This cap fits standard-size radiator filler necks commonly used on many performance and aftermarket radiators. It’s important to confirm your radiator’s filler neck size and required pressure rating before installation. Use this 16 lb cap if your cooling system specifications or performance goals call for that pressure setting.

• Compatible with standard-size filler necks on most aftermarket radiators.
• Check manufacturer specs for required pressure rating before replacing cap.
• Simple swap-in replacement — no adapters generally required for standard necks.

What materials and construction features improve durability?

The Moroso 63316 uses a stainless steel spring to resist corrosion and maintain calibration over time, while the solid brass retainer adds strength and heat tolerance at the spring mounting point. Those components reduce the risk of spring fatigue and loss of sealing accuracy that can occur under repeated thermal cycling in performance use. The construction choices support long-term, repeatable pressure control in demanding environments.

• Stainless steel spring for corrosion resistance and consistent force.
• Solid brass spring retainer for secure spring anchoring and heat resilience.
• Manufactured in the United States to Moroso performance standards.

How do I install and maintain the radiator cap?

Installation is a simple twist-and-seal onto a compatible standard filler neck—install only when the system is cool to avoid injury. Periodically inspect the cap for physical damage, sprung seals, or corrosion and replace if you notice leaks or pressure loss. Keep the cap clean and ensure the sealing surfaces on both the cap and neck are free of debris.

• Install only on cool systems; twist to seat and verify tight seal.
• Inspect seals and spring condition during routine cooling system checks.
• Replace cap if you detect leaks, weakened spring, or visible damage.

Who is this for? The Moroso 63316 16 lb radiator cap is aimed at racers, track-day enthusiasts, and anyone upgrading to performance cooling components who needs a dependable 16 lb pressure cap. It’s a straightforward, durable replacement for standard-size filler neck radiators where increased system pressure is desired for higher boiling point and stable cooling performance. If you require a different pressure rating, Moroso offers variants to match different systems and applications.