Thread: disappearing antifreeze

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My 70 Mustang sat for 3 weeks due to inclement weather. When I checked fluids, the antifreeze was a half gallon low with nothing on the ground. Never lost any before, not leaking through head gaskets. Can it just evaporate?

"Can it just evaporate?"

No. Have you checked for intermix? If there's no signs of leaks or intermix, your coolant was most likely consumed within the combustion chamber (s) while you were last driving it. pressurize the system & see if it holds pressure. If it doesn't, look for a cracked head or leaking head gasket. In any event (leaks or cooling system leak down), you can look forward to spending a fun filled day getting aquainted with your tools again

Did you check it just before you parked it? It might have been low then. That would spread the leak over a longer period, so the leak would be that much smaller and harder to see.

Look under your carpet, see if its the heater core.