[Wizard]

I would agree that the head was probably shaved wayy to much, didn't seal well with new gasket....caused a "blown" headgasket problem. Which is when the compressed air charge is forced into the cooling passages and adds extra heat and pressure to the cooling system. This also causes a slow overflowing issue. This keeps going until the level of coolant is obviously to low to cool properly and actually even too low for the water pump to be able to even move it around the engine. And your temp gauge is reading the temp of the air, not the coolant temp. There was no coolant to read.

Sounds like you overheated it a bit more than what you are telling us. Your head is now junk....period. They probably shaved it down to min. before and now it's warped again. It only takes once. On top of that, aluminum pistons in an iron block that overheats has a tendency to produce piston slap and scoring of the cylinder walls. Meaning: Pull your head and check out all the lovely scratches down the cylinders.

To fix your problem properly, you're going to need:

Gaskets for the whole motor
Not warped DOHC head casting (don't forget Hyundai's)
Main and rod bearings
Piston rings
Maybe pistons..........in other words she needs a rebuild now. Knocking is from piston slap, spun rod bearings, etc. Once you hear it once.....it's pretty much too late.

Wiz