+1 on what spaceworm said.
I have cleaned some really funky,nasty,dirty engines with the Dawn and it makes them look good as new. The crockpot method works well too, you will need to disassemble your engine to remove any plastic or rubber parts from it first though. I would recommend replacing the bearings after you clean it with the crockpot method. DO NOT plan on ever using the crockpot again for Human food!!
Also, should you have any pets around while you are using the antifreeze method , DO NOT let them get anywhere near the crockpot. Dogs/cats are sometimes attracted to the sweet smell of the antifreeze and shoud they drink it, it will kill them.

If you are just trying to clean the outside of your engine such as the crackcase and carb , I would say the DPD would be the least effort with the best results. Get you a stiff old toothbrush to get into the nooks and crannies after you let the Dawn sit on there for a little bit. I think you will be pleased with the results.
JMc