Driving on the highway, the screen on the dash says the AC (it is March in Michigan) has been turned off due to Excessive Engine Heat. We stop and check under the hood. Nothing seems to be wrong. 30 minutes later drive on. Same issue. Next day car is okay, almost, starts again after driving for 20 minutes. After an hour it is back to normal. Had the thermostat changed once before because of this in another car. Is it the thermostat or a sending unit?

Update from Apr 1, 2017: Since I first put my complaint in the car has had the issue come on the dashboard 5 times. And gone off 5 times. Never the same thing making it come on or go off. The car runs fine. The outside temperature can be in the 20s and as high at 60s. Sunny or raining does not make a difference. Have had it scheduled to go in the shop but on the way it stops doing it. Been driving the highway and around town so speed or stop n go driving does not matter either.

Purchased the 2010 Equinox LT. Test drove it, and it ran great. My wife drove it to Atlanta the next day, and it overheated..."AC off/engine overheat". Took it back to dealer who then replaced the radiator, and topped off coolant. Picked it up, drove it the next day, and the same thing.

Long story short, dealer told me that they had put enough time and money into it, and that was that. Told me I should have purchased the extended warranty $6000 which was half the purchase price. Carfax reported to previous water pump and timing chain/belt replacement around 40000 miles.

Took it a reputable mechanic in my town, who did some research on this engine. Told me that GM made a piss poor engine-Eco drive 2.4L. Multiple problems reported he told me. It seems the drive belt or timing chain pushes the water pump, and the water pump on this engine can't stand up to the high rpms this motor puts out. Irritated that the dealer didn't check the water pump when they had it, since it showed up on Carfax. I'm beginning to think this piece of metal is actually a big ol ripe lemon.