Check the oil for water contamination will be milky looking...check all hoses for leaks/pin holes.
Check thermostat maybe stuck. If gasket leak not to big the leak stuff works...but follow instruction.
If you don,t flush most does not mix with antifreeze..water only .
Freeze plug may have a pin hole ..run truck watch close to find area that it may be leaking at.
Should do a pressure test on cooling system.
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