Plug 3/4in Cup

The Plug 3/4in Cup from BERT TRANSMISSIONS is a precision freeze plug engineered for transmission and engine block cooling systems where reliable sealing is non-negotiable. As a seasoned mechanic, you know that freeze plugs are critical expansion safety components—they allow coolant to escape safely if the engine freezes, preventing catastrophic block damage. This 3/4-inch cup-style plug is the OEM-grade solution for builders and restorers who demand stock-correct fitment and proven durability in high-performance and street applications alike.

Manufactured from solid steel and finished with zinc oxide plating, this freeze plug combines corrosion resistance with structural integrity. The zinc oxide coating protects against rust and oxidation—critical in wet environments and long-term storage—while the steel core maintains the cup's ability to seal reliably under temperature cycling and pressure fluctuations. At just 0.01 lbs and measuring 2.2 x 0.35 x 3.05 inches, the compact form factor fits snugly into engine block and transmission core plug cavities without interfering with surrounding components. The cup design creates a pressure-balanced seal that responds predictably to thermal expansion, making it the trusted choice for vintage restorations and modern builds alike.

Transmission builders, engine rebuilders, and classic car restorers rely on BERT TRANSMISSIONS freeze plugs when original equipment specifications are required. Whether you're rebuilding a street transmission, a vintage engine block, or preparing a high-horsepower combination, this 3/4-inch cup plug ensures proper coolant circulation and emergency relief without leaks or weeping. Installation is straightforward—simply press or hammer the cup into the block cavity until fully seated, making replacement straightforward during any overhaul. Stock with several units for complete peace of mind during long-term ownership and storage.