If your household A/C is undersized and can't keep up set at 75* do you think turning it down to 68* is going to help?

It is not a throttle.

 

No it has never boiled over but when the gauge is all the way up the engine will stall sometimes and does not want to restart.

 

I will get that solenoid for the carb once we get the overheating problem fixed. The shroud fits closely , it is about one inch away from the fan blades. we are thinking of buying a mechanical fan that is designed to pull a lot of air for vehicles that have overheating issues. it is very possible the block could be sludged up or have corrosion in it but we have tried all the chemicals and engine flushes there is and they haven't made any difference. It seems to be shedding heat ,just not enough when its hot outside. In the morning and afternoon it doesn't heat up too much but towards evening when I am on my way home , the temp gauge stays close to the H the whole time, it does this every day with out fail and it has two fans that are pulling lots of air through the radiator and most of the cooling system it new. It has a new radiator,waterpump, and a new thermostat. I am to the point where am fed up with this truck and I am out of ideas to fix the issue.

 

Did you ever try to clean the fins out on the condensor in front of the radiator? If its full of dirt and not letting air flow well it can cause overheating. Having the AC on will accelerate the situation.