Mineral Buildup in Cooling Lines

[vtmecheng]

While winterizing our 2021 Prostar 6.0 (open cooling) I noticed a fair amount of mineral buildup in the cooling system. I pulled a couple of the cooling hoses and confirmed that a good layer has built up, with larger amounts at joints and transitions. This mineral buildup also completely clogged up the coolant crossover line. Does anyone here run something like the Star Brite product or cleaning vinegar through the engine cooling system for cleaning mineral or is this a leave it kind of situation? 

[markn]

Assume when you refer to "mineral build up" you are referring to calcium carbonate and magnesium carbonate.  If that is the case, it would imply your cooling source is "hard water"; high in calcium, magnesium and possibly alkalinity.  Build up usually occurs in areas of high heat transfer and/or when water evaporates to dryness leaving the dissolved minerals behind.  Without the presence of heat, calcium carbonate usually does not form an insoluble deposit unless the pH is 8.2 or greater but can still form from evaporation to dryness.  Doubt the pH of your water is as high as 8.2.  With heat it can precipitate at much lower pH levels.  (inverse solubility to temperature)  To dissolve mineral deposition, acidic solutions work the best.  Not familiar with MC cooling system, but if you do flush with a weak acidic solution, you MUST passivate the newly cleaned  metal surfaces by circulating an alkaline solution.  Flushing with  weak acid will expose the internals to corrosive conditions (no matter how mild the acid).  Passivating the surface will stop the corrosion mechanism.  (If using only vinegar, probably not necessary, but it is such a weak acid you may not get much cleaning.)