Now would be a good time to take the block to the car wash for good cleaning. Power wash the coolant area and the oil galleries as much as possible. Presoak the block in simple green or your choice of degreasers. The water passages can be poked and scraped with what ever tools you can get in there with. If you have a power washer or can one, use the RED pinpoint tip to really get into the depths of the coolant areas, be sure to remove the drain plug at the back and back flush though the opening. A wire brush on a drill motor makes fast work of cleaning the block openings and de-rusting the rest of the block. The degreasers will clean the inside.
