[MickeyRaySinatra]

Man, I love my '13 ATS 2.5l, but I am about to cry! This car will not stop overheating! I started having issues with the car about 8 months ago and the dealership fixed the engine mount issues and the touch screen display. Now My car has been in a shop for 5 months from overheating. I felt cool liquid dripping on my feet while driving and the dealership couldn't figure out what was wrong. Then my car started to overheat. I decided to take it to a different shop since it is out of warranty.
We have replaced the water pump and the thermostat. Everything seemed to be okay but he said keep an eye out the Radiator might be cracked because he seen coolant leakage, sure enough a few days later it overheated again and the heater stopped working and started pumping cold air. This time we replaced the radiator and he noticed the inlet and outlet were melted and coolant was pouring out. I just got this beautiful pain in my ass back. It drove Perfect!! I remembered why we were meant to be together forever.

Until.... about 20 minutes into driving it, I noticed the temperature gauge starting to go up and down just a little bit. "Don't panic, maybe they didn't bleed the coolant enough and there are air pockets" I thought to myself. Tested the Heater and noticed that it blew cold air again unless I accelerated. Pulled over and sure enough the coolant was bubbling. I let it cool down and it was still at the fill line. So there were no leaks. I called the mechanic and he verified that he bled the car for 45 minutes. Also said there were no signs of head gasket damage and no coolant mixed with the oil after the oil change. He also did not believe that the heater core was bad. I am still under the assumption that the heater core could be bad.. its better than a blown head gasket.

Any ideas?

Also, if it is the heater core, can we cap the heater core off on this model? At least until my bank account isn't arguing with me?

 

[rsingl]

For a head gasket test, the coolant needs to be tested for hydrocarbons. I believe that you will be able to find test strips at any of the chain auto parts stores. Exhaust leakage into the coolant system will pressurize the system and is the most common symptom of a head gasket issue. It will also create gas pockets in the cooling system leading to lack of heating except when the engine is running the water pump at high speed and will create rapid changes in the coolant temperature reading.

Your shop seems to be throwing a lot of parts at your car and that is a very strange symptom to have melted inlet/outlets on a radiator. If the cooling system actually got hot enough to have super-heated steam sufficient to damage the radiator tank ports then it definitely got hot enough to create issues with the head. I would get a proper test for hydrocarbon content in the coolant before putting any more parts on it.

Has the pressure cap been tested? It may be letting excessive system pressure build up leading to additional problems. I would definitely want that cap checked with a test tool before you connect a coupling between the heater feed and return lines to bypass the core. If the system is going over-pressure then every weak link you bypass will damage the next weakest link.

Once the root cause has been identified and addressed be sure and have the oil changed because it has likely been run far too hot even for a synthetic blend.

 

[angel71rs]

I agree shops are throwing parts at the symptoms and not finding the root cause.

I felt cool liquid dripping on my feet while driving

If you have an underdash leak, system loses pressure, overheats. Why it would be landing on your feet instead of passenger footwell I don't know. Maybe something underdash is guiding it towards driver side? How deep did the dealership go when they fixed the CUE screen? Shouldn't have been so invasive to cause a problem with heater lines. You still getting liquid inside the cabin?

Capping off lines to heater core: in the old days we would loop it. But it was easy to do, lot more room underhood.