I have a 98 gt 3.5l v8 mustang. And I'm at a lost for why it is over heating. So when i bouhjt it i new it would need qork c of previous owner.So this is a long story please bear with me. Last June it was overheating so I had the radiator, which was rusted, replaced also had the water pump, heads, and thermostat, this January had some rewiring done, did a coolant flush about a month ago, and did the thermostat again because the thermostat housing was leaking, found out that the thermostat had been cut so it was flowing freely, something they had did when I got my heads done at a different shop any who, after the new thermostat had been put in correctly it has been overheating. Had the heads tested which came back good, had the fan tested came back good.
Now to what it is doing, it only overheats when ac is on so anyone who says just keep it off well I live in Arizona and it was 108 at 10am you try having no ac lol. Also only overheats when accelerating/ at a constant speed. So when you are stopped it cools down. When ac is turned off it also cools down. Also just FYI the ac compresser stays on when it is over heating. Any help would be very much appreciated thank you in advance.