my chevy cobalt keeps getting hot after changing thermostat
Asked by linuxftw Mar 10, 2016 at 09:22 PM about the 2006 Chevrolet Cobalt LTZ Sedan FWD
Question type: Maintenance & Repair
The engine from cold will heat up to 221 degrees then turn on the fan. It might cool down at first to 185-190 but then slowly creep up past 221 and hit 240 before I shut off the engine. The cooling fan is working normal and stays on at these extreme temps. I have replaced the thermostat and the coolant with dexcool, and made sure the system was purged of air bubbles. The car does not have any coolant leaks. I'm thinking it may have a plugged heater core restricting flow, I haven't pulled the heater core hoses off to see if it doesn't have good flow or done a chemical test to see if it's a head gasket issue. Has anyone else had these same symptoms and have any good pointers. i don't want to just start throwing parts at it if I have overlooked anything obvious.
Thanks
10 Answers
The heater core is not the issue,if fans is running right and there is no fluid lost,you have a bad water pump.
if it is a head issue,you will have coolant lost out of the tail pipe or in your oil,if you have none of these your pump is bad.
I didn't think a water pump could fail that way. I'm used to older motors that the pump is an impeller that doesn't wear out and the only failure is a leak at the bearing. I guess these newer cars have pumps made of plastic parts or impellers that are of a soft material?
No,there not plastic there metal impellar,but they where down and want pump right,change the pump,you will fix your issue,if you are not losing coolant.
Yeah it doesn't have the signs of typical head gasket issue, no white smoke or smell of coolant burning and no coolant in the oil either. Gonna change the pump and hope for the best. Thanks for the quick replies! Two heads are better than one sometimes.
Just so you know a plug heater core can cause a 2006 Chevy cobalt 2.2 to over heat the engine
I have the same problem..New water pump, and hoses, still doing the same thing..
You can check underneath your car and see if there’s coolant coming out of the AC drain tube. If so then coolant is probably leaking into your heater core box from a defective heater core.
