Q: The cooling mood on my 2007 chevy cobalt came on out of nowhere. I had a guy pour antifreeze in and it was okay until yesterday.

Hi there. Check the coolant level to see if there is any coolant in the radiator. If there is no coolant in the radiator, then fill up the radiator with water and perform a pressure test. Check to see where the coolant is draining out of and fix that item. If you cannot find the coolant leak, then check the engine oil and the transmission oil to see if they are milky. If the engine oil is milky, then the head gasket could be split and causing coolant to go into an oil jacket. If the transmission oil is milky, then the radiator has a split and is forcing coolant into the oil cooler on the radiator.

If the coolant is full and the engine is overheating, then there could be an issue with the thermostat, water pump, head gasket, or radiator cap. Check the radiator cap and see if it holds pressure. If the cap does not hold pressure, then replace the radiator cap. If the thermostat is not working, then the coolant will heat up quickly and either make the engine overheat fast or overheat at a high temperature, but not sever. A burned head gasket or a failed water pump will make the coolant overheat very quickly and cause the computer to perform a shut down. If you need further assistance with your vehicle, then seek out a professional, such as one from Your Mechanic, to help you with your engine overheating and shutting down while driving.