overheat on 1998 Subaru Legacy

Engine overheats and antifreeze is lost through the overflow. Have replaced head gasket, water pump, thermostat, radiator, radiator cap and find no water in oil or oil in water. Car heater works fine. Any ideas?

Asked by for the 1998 Subaru Legacy
I have seen these heads develop cracks. Did you have a machine shop pressure check the heads while you were doing the head gasket work? Did you have both of the heads re-surfaced while they were off ?
The head gasket was replaced by a repair shop during a used engine installation. I do not know if this was done but I would assume he must have checked flatness. I do not know what made him change the gasket and seals.
Forgot to mention that engine was pressure tested by the shop after the HG replacement
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I just replaced Head gaskets and had heads checked on my '97. So far so good. there any in the engine? Also if you have an electric fan instead of a manual run belt may have a fuse blown or a bad fan assembly...or water heat sensor that senses the water is getting hot and turns the fan assembly on?