My cooling system is going through about a half gallon of anti-freeze every week. I thought it might be the head gasket but I had a guy do the Napa Block tester on my coolant reservoir and it did not turn colors. What additive would you suggest I add to the antifreeze to seal it? I am just wanting to try a couple quick fixes before I pull the heads. The same guy also told me that he thinks the gaskets that seal the intake are bad and that is how its probably leaking and burning off the coolant. None is ever on my garage floor and the catalytic converter is throwing a code. Click the link below to learn more about Napa Block tester.
https://www.napaonline.com/napa/en/p/BK_7001006/
https://www.napaonline.com/napa/en/p/BK_7001006/
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