Cleaning an engine block can be intimidating because you might be concerned about damaging the rest of the machine. Fortunately, it is fairly easy to clean rust off an engine block as long as you use the right materials and take your time. You can remove all the rust using tools you likely already have in your toolbox.
Get your cleaning supplies ready. Fill the small bucket about half full of hot water. Also, attach the wire cup to your drill and make sure the drill is charged.
Wash the engine block with the wire brush. The majority of the rust can be removed using the hot water and the wire brush. Dip the brush in the hot water, tap it against the side of the bucket and scrub. Use a cleaning rag to wipe down the engine block periodically so you can see where you still need to scrub.
Get rust out of small nooks and crannies using the wire cup on the drill. This will let you remove rust from small corners and crevices. Always watch where you are drilling because the wire cup can damage wiring and paint. You only should use it to get rid of rust in places you cannot access with your wire brush.
Wipe down the engine block. Use a clean rag that has been soaked in hot water. Then repeat the process with a dry rag to remove any remaining moisture.
Treat the engine block with WD-40. If you have the option of spraying it down from all angles and then letting it sit in the plastic bag for a few hours so the fumes do not spread, then do so. If not, spray it down in place and use a rag to work the WD-40 into any areas you cannot reach with the spray.
Some people use muriatic acid to get rid of rust on engine blocks fast. However, this can lead to serious problems if you do not get the acid completely rinsed off because it will corrode your engine block.