Subaru GL overheating?

A common cause of engine overheating is insufficient cooling.

If the engine is new, the radiator fluid is probably fresh as well. The first thing to check is the radiator fluid level.

If the fluid level is ok, the water pump or the radiator may be suspect.

I still think it can be the thermostat or some blockage somewhere. Most cars overheat when it's not moving because there is no air flow to cool the fluid in the radiator. If your car heats on the freeway where the fluid in the radiator gets really cool, then the engine is not getting that fluid for some reason so it's a flow issue and the first thing to check is the thermostat.

type into search box

how to check a over heating car

and thermostat can stick any time as well as a leak might happen

high speed its a dirty radiator most likely a no flow thing a lsow flow thing dirty radiator or soft hose perhaps