Chrysler Repair: 03 3.3L minivan overheats w/o gauge going H, head gasket leak, radiator hoses

Question
Hi folks, I appreciate any help with my wife's Caravan 2000 3.3 sport It is overheating, radiator spitting out coolant and there is no engine light on. The gauge temp will only read the temp when the key is on but once the engine started it goes back down, radiator fans were off as the engine was heating up but will work once A/C is on. I did change coolant sensor thinking that was the problem but it did not fixed it.

Answer
Hi Wash,
It is normal for the fans to come 'on' when you activate the AC. The issue is then why is the coolant sensor and gauge not detecting the overheating? I would start by considering whether the pressure cap has failed and is allowing the warmed up and expanding water to leak out of the radiator, which leaves an air gap in the system in the area of the coolant sensor. Take a look at the rubber gaskets on the cap, and maybe just replace it even if it looks OK.
The next possibility is that, if the overflow is starting to occur quickly after the engine is starting, is that there is a head gasket leak on one of the two cylinder heads, and that is allowing exhaust gas to pressurize the cooling system beyond the limits of the cap to bear. That would be accompanied by bubbling/girgling sounds in the engine and radiator hoses along with the ejection of coolant from the overflow bottle. If that were the case, there would likely be the emission of copious amounts of white smoke (which has a coolant smell) from the tailpipe when you start up the engine from cold, because some of the coolant would be drawn into the engine when it was previously hot and then cooled off. So see if you have that symptom.
It is also possible that after you changed the coolant sensor that you had some air trapped in the system and that it worked its way out, but that left you with an under-filled system. So that would be the optomistic possibility.
So consider these possibilities and let me know what you observe or how it works out. It is also possible that the radiator is clogged but the van is pretty new for that.
Roland