Car started overheating a month ago. Changed radiator cap, replaced thermostat, replaced fans with new mishimotos. Bled the cooling system several times. Car works perfecly fine without the AC running. Once AC is on and I run the car & I stop on the side of the road & the coolant is spitting out. What can it be?

 

Water Pump?

 

You probably have a radiator leak. When the ac fan kicks on and fling the coolant everywhere. I bet your hood near the reservoir and upper radiator hose have splash spots. I just did a mishimoto oem rad and z1 master hose kit replacement. Took me 16 continuous hour. Took probably an hour worth of breaks but I didn't cut any corners. Old hoses are very hard to take off. Best if they're cut off and you're left with some corroded nipples/pipes. I used a wire brush and cleaned it up. Flushed the motor and replaced all 17 hoses. Adjustable channel looks is a must. Different sizes help especially with the heater hoses and tight spots.