It over heats with Ac on have had about every new part installed

First wife overheated it and split radiator and warped the heads drove to far. Reputable machine shop did work. Didn't overheat all winter no ac. Summer started in again. Took to Nissan and they tried to figure it out. Couldn't hence cross over pipe that was ok. They said it wasn't Nissan parts and thermostat wasnt ,tore apart and it was. They don't know ether. They suggested I take it back to my mechanic. That's why the job was all done again under warranty and replaced all the parts since was apart again. Thanks hope to hear back

Ac off it don't over heat. The fans have three speeds and they check out with diagnostics. My thought fans running backwards they working fine per Nissan and Fidlers machine shop. No combustion gas in cooling system ether. Ac high low side checks out ,right specks

More questions if you have patience. Just trying to isolate any and all conditions-when it overheats , with the A/C on, as originally stated, is that when its sitting idling only , or will it overheat , even at cruising speeds (50-65 mph). In other words --THE ONLY TIME IT OVERHEATS , is sitting idling with the A/C on. If you turn the A/C off it runs normal temp , and off idle (normal driving) with the A/C on it runs normal temps.?

When idling in park and driving with no ac don't overheat. Ac on idling in park won't over heat. Drive the car no ac don't overheat. Drive the car and turn on ac go half mile it's ready to boil over.

This ones really got me curious!! I wish it wasn't so far away , this is my kind of challenge, unfortunately at this point , with what you've told me , my next step would be to drive it with a scanner and monitor any data relating to fans and A/C clutch etc. I presume NISSAN was able to duplicate symptom and tried for more than just a few minutes. Do you know what skill level the tech(s) where , that were working on it?

The tech skill level I don't know. Shop manager don't know either,at Nissan. They try to blame a different shop because it wasn't Nissan. They wanted to check catalytic converters for being plugged. Didn't replace no loss of power. Bolts rusted so we will have to replace. They were just throwing parts at her. I told them to check hubcap bearing Ha. They were bleeding me dry. So I took it back to my mechanic. He has had it on his scanner during drives. He says its normal. He is on a data base service he pays for monthly and I think it has everyone befuddled. I don't give up easy but my wallets getting a little thin. My warranty work has my mechanic upside down now to. Thank you