Manifold Expansion Filler - 6in Tall

The Manifold Expansion Filler – 6in Tall from CSR PERFORMANCE is a precision coolant system component engineered specifically for Chevy V8 engine modifications and custom cooling setups. This water neck filler assembly serves as the critical interface between your intake manifold and upper radiator hose, managing coolant flow while accommodating high-performance engine bay configurations. Whether you're building a restomod, upgrading to a stroker motor, or installing a new intake manifold, a quality expansion filler ensures proper coolant circulation and system pressurization without leaks or air pockets.

Machined from lightweight aluminum and finished in clear anodize, this manifold expansion filler features a 15-degree angled neck design that optimizes hose routing in tight engine compartments while maintaining structural integrity under pressure. The 12 AN male fitting provides a secure, industry-standard connection point compatible with -12 hose and adapter systems, while the integrated o-ring seal eliminates reliance on gasket stacks and reduces leak potential at high coolant temperatures. At 6 inches tall, this filler neck provides adequate expansion chamber volume for proper air venting during warm-up cycles, critical for preventing vapor lock and cavitation in modified engine builds where stock cooling designs no longer apply.

This expansion filler is ideal for engine swaps, performance builds, and custom cooling system installations where manifold-mounted fill points are preferred over traditional radiator caps. Mechanics and fabricators frequently use it when upgrading to aluminum manifolds or custom intake designs that lack factory cooling provisions. All necessary hardware is included, making installation straightforward for those comfortable working with coolant systems; simply drain the system, remove the old water neck, and bolt this assembly in place using the supplied fasteners. Ensure your system is properly bled and pressurized after installation to confirm o-ring sealing and eliminate air from the cooling loop.