Mine is green and the concentrate was mixed with distilled water, apparently that`s important. If you buy 5L packs of it ready to use it is already diluted(? they use distilled/demineralized water).
That engine can get silting in the passages at no6 cylinder, leading to overheating, requiring an aggressive flushing. Is doing the coolant connected to that by any chance?
2005 Integrity 386 "Sojourn"