Engine overheating

Two months ago my wife was driving my Jeep home from work (it was during January - sub-zero temps) when it started to overheat - she didn't notice the temp gauge rising. She drove it until it completely shut down. Because of the cold, and not being able to get it into a mechanic it sat at our house until we could work on it. My son is a trained mechanic and we set about trying to determine if it was a workable situation. I had recently installed a new alternator and water pump just before this incident and since then we have put in a new radiator (the old one was cracked), serpentine belt, and belt tensioner. A complete oil change was done as well. We have purged the cooling system as best we can but there still seems to be a lot of air in the system. The heater core seems clear but I am not getting any heat in the cabin. Today as I tried to go to work it overheated again (after we thought we had it fixed) and I watched as coolant gushed out the overflow tube on the coolant reservoir. Please respond with any suggestions! I love this Jeep and would rather not get rid of it!

Thanks for the reply but I got my answer today. My son brought out a test kit to check for a warped head (by checking for exhaust gases in the coolant). Got a positive result. :( I guess the next step is removing the head and having it milled (if possible) and replacing it with new gaskets and bolts.

This morning my 1994 Grand Cherokee cut off at the light it started shaking and hissing and smoking from the grill. The temperature went past the red. What could have caused it to run hot. I checked all fluids everything was filed. The car had been sitting for about 10 months prior to me driving it today.
Thank you for your help

Yeah It had some in there and When I parked it the fan never came on! I was at the light for about 5mins at the most.

99 jeep grand cherokee laredo, my car was overheating and the fan wasn't coming on. I had a new radiator and fan put in about 2 months ago. Its overheating again and has no heat.

Overheating had radiator replaced and fan as well coolant needs to be filled constantly but have found no leaks when it starts to run hot, I turn the heater on. Now my heater is blowing cold air. Also the radio has been cutting out.