A buddy of mine has a 89 shadow we always seem to be working on... Anyways we flushed his heater core a couple weeks ago because it was clogged and was putting out no heat. We got a TON of "mud" out of it. I noticed while we were messing with the car that inside of the brand new radiator seemed to have a bunch of sludge/mud on it. A swipe of your finger inside the radiator and it was covered in it. I told him then we may have to flush the whole system but we were out of time. He called me today and the heater core is plugged again less then two weeks later. So now we need to flush EVERYTHING. We flushed the system with straight water when he first bought it so I am thinking we need to use some sort of cleaner this time. I think in this cars past it had a blown HG and water and oil mixed and it was improperly flushed. So I need something that will cut the oil, not hard water deposits. I did a bunch of googleing and found two things that are supposed to work great for this. Dish washer detergent or simple green. Has anyone used either of these? What kind of results did you get? Just looking for a little extra info before we dive into this tomorrow morning.