Expansion Plugs 41/64 (.635 ) 10pk

Pioneer Expansion Plugs 41/64 (.635) 10pk are precision-engineered core plugs designed for sealing freeze holes and coolant passages in engine blocks during repair and restoration work. These plugs are ideal for mechanics and machine shops involved in engine rebuilds, block repairs, and custom cooling system modifications.

Constructed from corrosion-resistant steel, these expansion plugs feature a tapered cup design that expands mechanically upon insertion, ensuring a secure fit against the block casting without the need for sealant compounds. This design helps maintain seal integrity across various temperature extremes and prolonged contact with antifreeze and water.

With a 10-pack quantity, these plugs are suitable for single engines or small fleet maintenance projects, providing adequate inventory without excess waste. Their compatibility with both cast iron and aluminum blocks makes them versatile for a range of applications in automotive repair.