question for the experts(overheat issue)
 

My boss is borrowing a friends X and has a weird issue. I really didn't search, just figured I start a new thread. She tells me while driving with a'c on and comes to a stop, the temp gauge moves past middle, but not to red. Once the temp moves a bit, the truck shuts down by itself(saftey feature????). Let the engine cool off a bit and it starts right back up. I haven't had the chance to look at it, but my guess would be the thermostat or waterpump. Sorry for the vague info, this is all she gave me. It just sounds weird that when the gauge moves just past middle, the truck shuts down. I've never had this type of issue, so I have no clue. Let me know what you guys think. Thanks a bunch.

My boss just told me when she was driving this morning, a/c off sitting at a light, the temp gauge moved past middle, light turned green and temp gauge when back to normal. thermostat, waterpump, or air in system??

Maybe a stuck thermostat?

That's what my thought was, but what is throwing me off is that she said it shuts down when it goes past middle, but not to red.

update: it is a 3.0 x3

Agreed.. Thermo is probably causing the weird reading and failsafe is shutting it down. Easy DIY.... what year and how many miles? I assume it hasn't been changed out prior to this?

I have no idea what year or how many miles. I glanced at it in the parking lot and it seems to be an 05-06, but not sure. The truck is my bosses friend. She had to borrow it, her 4runner is in the shop. She knows I work on my 540 and the wifes x5 so she figured she ask me about the issue. My guess it is probably original. I'll let her know it is probably the thermostat.

Thanks a bunch guys. Your help is greatly appreciated.