So I'm running  winter fronts in my grill. When moving my temp is at 190 sometimes a few degrees more. But when I stop say at a light the Temps quickly drop to the low 180s. I would think they would stay at 190. I'm thinking the fan is kicking in and cooling things down. So what good is it to have the winter fronts.

If the fan was kicking in you would no it sounds like a jet taking off. I also have a front on mine would drop to 160 or so  but after changing the thermostat it stays right at 190,itsright around 30 degrees here. Does it come back up to temp when you take off again 

Do you have the heater cranked? You'd be surprised how much heat the heater sucks out of the engine.

I changed the thermostat didn't change how it runs. 

Good thermostat should be completely closed by 188*F on a live data tool.

BUT Just because it's closed doesn't mean the engine will not continue to cool, thus my heater blasted comment that was ignored.

Not ignored by me...

I know to a certain extent that yes you can suck the heat out of the engine. It can be done by cranking the temperature knob to HOT and fan on HI and the block temperature will start to fall while the truck is idling at a stop. The reason behind this there is no thermostat to the heater core and it will continue to dump as much heat as the fan will allow. The fact remains under power at road speeds the block temperature should still rise above 190*F and hold good temperature other wise. I know for my truck if the cab temperature is comfortable and the temperature knob is about middle and fan is on the 2nd Speed setting I'll never drop below 188*F while out and about in the winter.

Sounds fairly normal. These engines don't use the thermostats very much. The Crack open and fluctuate open and close while cruising that's usually why they fail. Your thermostat sounds nornal. 

I've ran it with the heater on and off didn't change. In fact the heater is warm but not blazing hot like I remember. I change the thermostat two weeks ago and the heater core and evaperator two months ago. I think the heater air cooler when at idle also.

 

7 minutes ago, lrhull said:

I've ran it with the heater on and off didn't change. In fact the heater is warm but not blazing hot like I remember. I change the thermostat two weeks ago and the heater core and evaperator two months ago. I think the heater air cooler when at idle also.

 

You may want to check your blend door actuator coupling. Mine is shot and it acts similar to yours and my heater core is new. 

Maybe you have an air bubble in the coolant system. I'd pull the cap when it's cold and idle it until hot if you have a bubble it will come up after some time. Just be sure the coolant cap is higher than the rest of the system. While your there replace the radiator cap if the pressure isn't high enough it could act funny as well.

I was just thinking the same thing, air in the system and mabee i need a new radiator cap.