Overheating after replacing Heater Core?

TBURNS.1

MEMBER
2007 CHEVROLET EQUINOX
4WD
144,000 MILES

I didn't have heat and there was a syrupy odor in car. I replaced the heater core, and I had heat and odor gone. A couple of days later the car started to overheat. Replaced the thermostat. After a couple days I noticed a coolant leak. Replaced the lower intake manifold gasket, which took care of the leak. Then I noticed the overheating only while idling. Replaced the water pump.

It seems it always runs okay for a few hours but then it comes back. Radiator fans are working, the temperature sensor I also replaced. There are no signs of a blown head gasket. No misfire, no gray smoke from tail pipe and no antifreeze in oil.

I have bled the system many times for air bubbles, vapor lock. It seems they are gone but then come back. Any suggestions please.

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi,

If the heater is working as well as the cooling fans, it does sound like trapped air in the system.

When you bleed the system, are you opening the bleeder on the water pump tower?

Do me a favor. I attached the directions below for bleeding the system. Take a look through the directions and let me know if you may have missed something.

One other thought, remember not to mix the traditional coolant with Dexcool, and let me know if it ever overheats at highway speed.

Let me know.

Joe

See pics below.

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