I will try to explain this as best as I can. I will assume that your car is not spitting water or steam from under the hood? If it is, dont drive it and contact your dealer ASAP.
If it isnt doing that, then the engine over heat fault, is a "false" negative, meaning the engine isnt actually overheating, but the car "thinks" it is.
Firstly, is your Cruze still under the 3 year, 36,000 warranty? If so, then any of this will be covered under warranty.
If not, then your Cruze will still be under the 5 year, 100,000 warranty and coverage will depend.
You are correct that this is a known issue, there is infact a service bulletin that covers this issue. Cannot remember the exact number of it, but I have it somewhere.
The service bulletin clearly documents the procedure the dealer must follow when investigating this error code (AC off due to high engine temp).
Step 1 - Verify software revision in engine computer for engine coolant temperature control, reflash to latest revision if not. Most modern engines, in order to create better fuel economy, have migrated to a electronically controlled thermostat, in place of the traditional mechanical spring style. This allows the engine temperature to stay much more constant, and the fuel map can be optimized for maximum economy. Parameters in earlier versions of the software were set too tight, and did not compensate for variability. The reflash inputs new parameters. This must be performed first, before any hardware changes are made or the dealers warranty charges to GM may not be refunded. If your vehicle is under the 3/36, this will be free. If not, it is a flat rate $87 to reload. There has not been a recall on this as it is not a fire or safety risk, the error causes the engine to go into a safe mode to protect the engine from overheating (althought it actually isn't).
Step 2 - If step 1 doesnt resolve problem, verify thermostat value operation. If incorrect, replace. This will be covered under both the 3/36 and 5/100 warranty.
Step 3 - If step 2 doesnt resolve problem, monitor and verify engine temperature sensor. Replace if outside of allowable tolerance range. Sensors are covered under the 3/36 but not the 5/100 (this is clearly documented in the 5/100 warranty disclaimer on the GM site). However, this is a less than $100 fix.
Step 4 - If step 3 does work, evalute entire cooling system, radiator, water pump, etc. All of this should be covered under the 3/36 and 5/100 warranty, unless GM can show evidence of neglect.
Unfortunately, each step takes time and usually means multiple trips to the dealer as in my case. Each time the dealer did a step, they were unable to duplicate the failure at the shop, but within 24 hours of taking the vehicle home it came back. Mine ended up being Step 3 to resolve.
My dealer worked with me on the charges, allowing me to apply the money I paid for the reprogram to the sensor replacement. I have subsequently contacted Chevrolet directly and have reached a satisfactory solution with them that will keep me as a customer for many years.
So this really all comes down to where you are with your warranty. I assume that your have had your car since new, or at the very least the original warranty was transfered to you when you purchased it used.
Recalls are usually only issued when it is a serious safety or fire risk. This is neither one. I personally do not hold GM accountable for updating my car computer to their latest version of software, for free, for the entire life of my vehicle. In my case, I was outside of the 3/36 but inside the 5/100.
If your dealership is saying they "dont really know how to fix it", I suggest you contact another dealer as this is a well known and documented issue. Along with a process to follow to investigate and correct.
But again, each step will take time unless the error comes back on immediately after the step is tried. If it is truly is a problem with the water pump or a larger item, steps 1-3 will not work at the dealer before you pick it up the first time, and will be corrected.
GM has to draw the line in the sand somewhere with warranties, the 3/36 bumper to bumper is solid. The 5/100 covers most of the big items.
Back to my first point, unless the car ACTUALLY overheated, this will not be a super expensive fix.