Flush coolant system on my 9U

Forget all those "home brew" remedies and get the cooling system cleaner/flush from Cat.
If you need something more aggressive than that get a hold of a local rep for industrial cooling systems water treatment (cooling towers, heat exchangers, etc) they have some excellent descaling products. The best way to utilize them is to rig up an independent pump circulating system where you can filter out the crud and control the concentration levels.

I don't have a home remedy for the scale other than remove the radiator and take it to a reputable shop for cleaning. But for the oil problem we use Cascade for oil in the cooling system on a regular basis. We use the stuff for automatic dishwashers due to it don't foam up. Depending on how much oil is in the cooling system we will fill the system with water and add one container of cascade and runt the machine for a shift. Then let the machine cool enough to get the cap off and pump a little fresh water in to flood the oil off the top before you drain. This makes a little bit of a mess but you don't spread all of the oil back down through the radiator. keep doing this over a couple or 3 shifts and it will come clean and smell nice as well.