2009 Aveo Losing Coolant and Overheating

[Bxboxer219]

Hi,


I have had my aveo for about 3 years. About a year ago, the vehicle started getting hot. I got a new head gasket, thermostat, and water pump, and the car drove fine for a few months. Eventually, it got hot again, to the point where it hit the red overheat mark. I took it to another mechanic, who stated that the head needed to be refiled/resurfaced. He sent the head in and installed, and I got another thermostat, head gasket, and water pump.


The past few weeks I've noticed a few things:


1. The temp gauge sits a bit under halfway when idling. (Normal)
2. When I drive the car, I notice the gauge go above halfway, and drop to normal (which I believe let's me know the thermostat is opening up)
3. When driving locally, the car drives fine for the most part.


After having the car back for a week, I took 3 30mile trips over the course of a few days, and noticed that the car started getting hot. (Around 3/4 of the way)


After letting it sit a few minutes, I checked the water level, and noticed it was low, so I added more. Anytime I drive the car 50-100+ miles, it gets hot, and I have to add water. I've taken the car to the mechanic a few times.


He he let it sit idle, and said it doesn't get hot. There is no whitish residue under the engine cap anymore. The mechanic cannot find any leaks, and will be replacing a part that connects to the water pump.


If anyone has any guidance or similar experiences, it would be greatly appreciated.


Thanks for your time.

[The_Limey]

Have you tried testing the radiator cap itself? They're usually set to open at around 1 bar for safety purposes, but can fail and stick open. In order to raise the boiling point of the water/coolant in the system above 100°C, the system needs to pressurise and a faulty radiator cap won't allow this leading to cooling issues. It's always best to start with the basics.

[ChevyCC]

Does the radiator fan come on once in a while when it gets hot? It should come on when temp goes up.
"I notice the gauge go above halfway, and drop to normal" shouldnt go above half, maybe they installed aftermarket thermostat with different opening temp?
Coolant controls heat better, instead of water.
Coolant deposit cap?

[PoisonIvy]

Replace the coolant resevoir cap. They've been known to fail, which reduces the pressure, and the coolant/water boils at a lower temperature then it should if the system is pressurized.