After mentioning to my mechanic that there was air in the system, I have the water gushing sound at the firewall, he says there's a screw on the engine that can let the air out. If true, anyone know where it is and the process.
I was thinking the whole system needed a purge, but this would be easier.

 

Let the car cool, jack up the right front corner or simple park the car with the front end higher then the rear.
Remove the cap on the rad hose, start the car turn the heater to full hot.
After about 5 minutes turn the car off , check the coolant level and top off.
The bolt is on the top of the head by the top rad hose beside the valve cover bolt

 

Just make sure its not just a case of the expansion tank being empty before opening things up. Being low on coolant will often cause noise like that.

 

Thanks OB, but where does removing the bolt come in?

 

It really doesn't! I've never used the bolt or plug to burp the cooling system, just the nose high method.

 

Some ecotec engines have the vent, I don't think HHRs do. Unless it is that bolt right next to the hose connection in the pic. I have never experimented.

 

It is that bolt, on our '03 Sunfire there is a fitting in that port and a hose to the expansion tank on the passenger side inner fender.
If you remove the plug then be sure you do it while the engine and coolant are cold!

 

Or take it to a reputable radiator shop, and have them hook it up to an "Evacuator" which pulls a vacuum on the cooling system.

Sometimes the "Nose High" parking suggested doesn't quite get all the entrained air out, and air pockets can lead to overheating, the #1 killer of Ecotec engines.

 

So remove bolt on cold engine, then???

 

That's what he said: "If you remove the plug then be sure you do it while the engine and coolant are cold! "