Once the block is completely stripped, it is blasted and cleaned in a
caustic bath. With all of the old grease and oil removed from this
process, it is magnafluxed. The magnaflux process checks for cracks
by placing a red metallic dust and magnet on the block. The red
dust fills into the cracks, making the cracks more obvious.
Like the block, the stripped head is also placed in the caustic tank
after it is checked for cracks in the magnafluxing process.