Chevrolet Repair: Chevy van

Question
I have a 2008 Chevy 2500 extended cargo van on the way home today my thermostat gauge shot up and on the dash it said engine hot a/c off it did it twice the first time I was sitting at a red light and the second time I was going about 25 mph what could that be and also I smell antifreeze sometimes stronger than other times but I don't have any antifreeze leaking on the ground and I don't have any in the passenger floor board

Answer
There are so many questions that need adressing. I will go through a couple of possible scenarios that may fit your situation.Starting simple:Thermostats do fail and quite often.Overheating leads to higher than normal cooling system pressure.Any weak link in the system can fail.One of those weak points is the heater core. If that sweet scent is apparent in the vehicle a heater core is most likely failing. There are drains engineered onto the  heating / cooling unit for the sole purpose of allowing coolant from a failed heater core to drain away from the interior to outside.You may not have coolant pooling up on the passenger floor but that does not mean the core is good.Another possibility is coolant leaving the system and entering the lubricating system via a failed intake gasket,or on rare occasion head gasket(s)No visible leaks but leaking non the less.With this kind of failure it is important to get after it immediately, or risk destroying the engine.You dont want to be running an engine that has it's oil contaminated by coolant. Only bad things can happen.Another example of excess pressure in the cooling system that can do in a heater core is the pressure from the combustion source.A bad head gasket. I hope this helps.