Originally Posted by JourneymanMike @Iceman2733
With the Alphacool's, you should use Mayhems Blitz Pro Part One... Alphacool's are usually full of loose solder and flux, from manufacturing, and need some serious cleaning, lest you get that Krap in your loop!
I have to add my few cents/pennies/[put any currency here
All my radiators are from Alphacool. All of them are 45mm. I simply require multiport option and 6x1/4" perfectly fit the bill. With cleanliness of radiator it's a bit of lottery. In general Alphacool is considered 'dirty rad' when new and you shouldn't save on flushing, but not all are terribly dirty. One thing straight - it's impossible to clean radiator 100%. All my radiators are done the same way:
- 10 L of DI/DM/distilled-whatever water - initial flush (add another 5L or more if you still get crap load of waste after first 2 bottles),
- after that one fill of water again and leave for a night with threads at the bottom - jiggle rad at various intervals,
- next day rinse and fill to the brim with isopropyl alcohol (using 99%) and leave it for a 24h jiggling at random intervals
- next day rinse and flush with 5L of DI/DM/distilled
- leave for a day or two in warm/hot place - on heater or in direct sunlight (depend on weather outside)
Voila. No need for excessive investment (well being connected to automotive industry I have stacks of water and isopropyl, but even purchasing it is dirt cheap, water about 1.5$/5L and 1L of isopropyl is about (equivalent of) 3-4$/1L which is enough for 2 480/45 mm rads) or vinegar. No matter what you do radiators always will contain impurities inside - every screwing/unscrewing of fittings, all of that leave residual waste inside (microscopic fillings or remaining of POM/acryl or paint from top of the chambers). All of that is impossible to clean 100%. At some stage cleaning of a cleaning of already cleaned radiator is just pointless overkill and adds significant amount of meaningless work for no gains. So far nothing exploded on my side and doing it every time same way..
Recently went back from pastel to clear see through coolant. Same procedure, no issues. I will add only that I do leak testing with some UPW like from Mayhems or Alphacool. It never hurts to spend a tiny bit more for something that is tested. 2L doesn't break a bank when you spend 1000$.