My apologies in advance if there is already a solution. Im new here.

Anyways so it seems my car is beginning to overheat. I have flushed the radiator and replaced the coolant, checked all the levels and its full. When im at a complete stop at idle the car will begin to overheat nearly reaching the red mark on the gauge. but whe i accelerate around or above 40 mph it will begin to drop down to normal and ac will only then blow cold air. Im completey stuck. any help would be great. even a link if this has happened to anyone else before me.

 

Check your fans to make sure they're working properly. The fans may be going bad and running at a lower speed than needed to cool the car.

The air conditioning compressor will require the cooling fan to operate at idle as long as the compressor is on. A quick way to check the cooling fan operation is to turn on the air conditioner. The cooling fan should come on with the air conditioner compressor. Some cars will have two electric fans, one is for the radiator and the other is the air conditioner condenser fan. Usually the radiator fan is closer to the middle of the radiator. The radiator fan is responsible for engine cooling, and the condenser fan is responsible for increasing air conditioning efficiency at idle and low speed.

 

I actually just had the fan assembly shroud replaced with a new one. The original dry rotted. Both fans are spinning perfectly.... I turned the car on and fan kicked on with the compressor when I'm driving but now that you mention it the compressor only seems to kick on when I'm driving tho. Not at idle.

 

so still overheating or no? that's the most dangerous part (kill the engine, aluminum low melting point!!! D: )

I think an air bubble in the coolant line can do this if it's stuck at the temp sensor. Might try to locate the temp sensor and see if it's possible for bubble to get there. Other than that if your water pump is working this doesn't make sense. You can buy a , comes with a thermocouple, although IDK if it's ok to get that tip wet, maybe get a wet thermocouple if they make those, and thread that through the line to measure the temp coming out of the engine to make sure it's not actually overheating.
If this differs from what the resistance reading is on the temperature sensor itself from the coolant, may just have a coolant temp sensor malfunction (replace)

 

how do you know it "only seems to kick on"

I thought similarly, only getting cold while driving, well it was low 35% on refrigerant and I was afraid of overcharging (probably didn't need to be). It's hard to determine without evacuating how much is in there, due to the two pressures (low/hi side).