Hyundai Repair: Overheating, combustion gases, head gasket

Question
I have a 2001 hyundai Tibereron ~ It keeps over heating ~ I have had the radiator, raditor cap, theremostat , head gaskets and valve cover gaskets replaced it has been in and out if the shop for months ~ the fan is running ~ I get it back from the shop and it runs ok for about a day then it starts ~ today it went to the H and then dropped right back down to cool ~ this did it a few times and I parked it ~ I have no idea what else they could do to repair this vehicle

Answer
Hi, Liz.  This issue could be as simple as having an air bubble trapped in the cooling system.  In fact, I suspect that's the case, that there's air in the system.  That's the typical cause for the temperature to intermittently go high and then fix itself.

The problem is that we don't know why the air bubble is there.  Is it because all the air simply was not removed during the previous work?  Or is it because the cylinder head is warped and, despite having a new head gasket, is nonetheless allowing combustion gases into the cooling system.  On your engine, I've never seen a circumstance that a head gasket was required due to overheating that the cylinder head was not warped beyond the specified repair limits.