Block

If the engine has been removed and disassembled, remove all core plugs and pipe plugs. Clean the cylinder block using solvent, preferably in a hot tank. Follow all safety and environmental precautions with regards to the solvents. Make sure all oil and dirt is cleaned from the cylinder block.

Make sure all oil passageways are clean. A rifle-cleaning brush is useful for this purpose.

Use a long, thin screwdriver to scrape the bottom of the water jackets through the openings in the top deck to make sure all scale and deposits are removed. Most engines have a "dead spot" at the back of the block where the coolant has to make a U-turn and drops any deposits. If the water jackets are not thoroughly cleaned, overheating will result.