1998 Aurora cooling problem

I need some help! My car has started running hot at speeds in excess of 60 mph. Below 60 never heats up. It will heat up and cut off ac and send alarm. It boils coolant out at this point.
Prior to overheating problem I had to replace water pump because it was leaking. A short time after that is when the over heating began.
I have replaced the recovery coolant cap and thermostat. I have carried to the dealer several times.
Some months back I had problems with skipping on occasions and the dealer told me that the heads were cracked. Well we go thru the process of removing heads , resurfacing and put back...still had the skipping problems.
Replaced 3 coils and elimnated the skip. Now I'm wondering if the heads are warped and causing the overheating problem???? HELP!

I would think if the head was warped and leaking coolant, you would see traces of it in the oil. What type of coolant are you using? Do you notice the coolant level dropping?

oh yeah...forgot to ask this... your front air deflector isn't by chance missing is it? Without it, the engine will run much warmer...especially at highway speeds.

I am using the orange type.....air deflector is in place.

so what was the problem? what did you end up doing?