What is the best method of cleaning an engine block yourself?
A bare block? Engine degreaser, wire bottle brushes though the oil galleys, soap and water wash, spray down with WD-40 to displace water and prevent rust.
I know a guy that used to clean his VW engine cases in his dishwasher.
If you are rebuilding the engine and the block is out of the car, then you should clean the engine with some kind of degreaser. If the engine is in the car, I’m not certain why you would want to clean the block. With all the electronics, there is too great a chance of damaging something. Instead of cleaning the engine block if the engine is still in the car, just spray a little RightGuard on the motor mounts–that’s all I do instead of taking bath.
If the engine is in the car, I’m not certain why you would want to clean the block.
It might be a show car that makes you go “ooooooooooooooh” whenever the hood is opened because of all the chrome and paint. That’s about the only reason I can think of to wash a car engine under the hood. Don’t they make a cleaner that you spray on the block, let it sit, and then spray off? I think I have seen such products at the auto parts store. If done carefully, it shouldn’t be any worse for the car than driving through the rain.