From what I've seen, it does allow the engine to warm up a little more...but only from just below the last hash before middle to on top of the last has before middle.Definitely check the coolant level, but the description makes me think it's a bad fan.
But first: Make sure it's really overheating. It's possible with the A/C off the computer will allow the car to warm up a little more before kicking in the fan. My old car would sit rock steady at 1/2 if the A/C was on, but if it was off it would go up to 3/4 before the fan would kick in and cool it back down to 1/2. I haven't turned off the A/C in my Cruze long enough to see what it does.
Sent from AutoGuide.com Free App