i recharged my ac 2 days ago, and yesterday i used it and the car overheated. i looked on the g35 forum bc maybe i used the wrong freon, and i saw someone say not to use anything that says "stops leaks" and mine did say that... do you guys think that's what's causing it? yes, i checked the coolant levels, everything is fine. please help ):

 

No that's probably not why. When you turn on the AC you are taking the heat from the cabin and putting it into the front of the radiator using two liquid-air heat exchangers.

First one is inside the cabin in the AC box, the refrigerant supercools as it's blown through the orifice and turns from a liquid to a gas, it sucks heat out of the air due to the energy needed to expand the gas. This raises the temperature of your refrigerant by X number of degrees. The refrigerant is then compressed back into a liquid in the AC compressor which generates a significant amount of heat turning the gas back into a liquid.

This superheated liquid then goes through the AC condenser which is directly in front of the radiator (or attached to it on some models), the heat then radiates out to the air where it is then usually sucked through the radiator (because they're sandwiched on top of one another).

This extra heat can push your system over it's limit if some other component in the cooling system is not functioning properly, might not be holding pressure, might be an old corroded radiator (especially if anyone has added tap water to it in the past, rots out the coolant system quickly), less likely but might be a worn water pump (usually starts dripping coolant from the front left side of the engine).

 

radiator and thermostat were replaced in january, so i highly doubt (and hope) that's not the issue. i'll take a look at the water pump tomorrow and see what's up with that, hopefully it's not that either.

 

It's probably not holding pressure, rent a pressure tester.

 

Or your fan motors are worn and not spinning fast enough, or a relay is blown and it's not spinning at all.