This is what happens when you forget the biocide... lol

[bmaverick]

That's some serious goo in those tubes. When a loop gets that bad, all of the distilled vinegar you toss at it will not really help much. You need to up the cleaner to a true radiator flush. Drain the loop and fill with the cleaner and about 1/2 cup propylene glycol. Run the loop with the computer off. With that amount of goo, there is no telling how long you will need to run the concentrated cleaner. Drain the cleaner, rinse the through the loop thoroughly, drain again and now replace the tubing. (The PG is to ensure that the pump isn't running on the cleaner alone.)