we have replaced the water pump, and reworked the radiator and plushed for posible cloggings,
but its still reaches the highest level.
but beforeit happend we have the cylinder head refaced.
and covers the 4 jet valves..
what might be the posible cause of the severe overheating.

bad thermostat

The pull cord to the engine is frayed, or you might have left the leaf bag on. It also might be time to sharpen the blade. If all else fails, you might try changing the kimchee.

take it to radiator expert and get presure test. check sencer and thermostat

Bad thermostat
Low coolant
Defective pump
Fan not coming on (defective motor, wiring or relay)
Leak

Did they actually do a flush or was it just a drain & fill? It should have been power flushed to remove deposits in the head too, & all fluid going back in, should have been new.

It is possible that with the removal of the head, some crud or gasket pieces got loose within it. Coolant flows through the block & the head - there could be an obstruction there. Hopefully, the individual that removed & reinstalled the head was more careful than that.

Replace the thermostat & gasket & check the coolant level first. When the vehicle is cold, remove the radiator cap (never remove a cap from a hot radiator), then start the car. When it gets close to normal operating temperature, the thermostat will open & u will see the coolant circulating inside the radiator. Add 50/50 mixture until it reaches the top & the level stays constant. Replace the cap & watch to make sure the fan comes on.

Swirling coolant = good pump
Fan comes on = good motor/relay

If it fails these tests, u will probably need to take it to ur local Hyundai dealer. OE thermostat & gasket r still available from Hyundai for ur vehicle.