Chevy Aveo 11, Coolant boils after replacing timing belt, water pump, thermostat and housing, valve cover gasket! Please read details!?

All were replaced at the same time, I don't think it is the head gasket since the car was working great before replacement. All part are genuine from GM. Expert, Please help me top troubleshoot it. If you are not sure, please don't mislead me with probabilities! Thanks It is not the head gasket for sure, the car was working fine before the replacement, not even overheating. The timing belt was due and the thermostat housing had a hair line crack so it needed to be replaced. Appreciate some of your inputs especially the one said to check the bleeding procedures.

Geo: Easiest things first

Easiest things first: Fill the Radiator and Start it with the Cap OFF. If water shoots out Compression is getting into the Water Jacket..Head gasket. If there are Bubbles, either you have air that needs to be bled or you have a leak that is letting air enter the cooling system. If you can rent a Cooling System Pressure Tester, do it. If you have a Plug on your Thermostat Housing, that is where you bleed it. You ALWAYS bleed from the Highest part of the cooling system. That's a Top Troubleshoot. pressure Tester


You have an air lock because the system didn't get filled properly after you did the pump and t-stat. Some cars are very difficult to completely re-fill. There are bleed procedures that need to be followed.


did you use a vacuum fill tool when filling the cooling system? Sounds like an air pocket is in the motor and heater core.


Thermostat backwards? the spring faces the engine. Trapped air, had one that was doing that, had to pull a heater hose off up high some air escaped and that was the end of the problem.


Make sure the fan is turning on. If it is then you might have a blown head gasket which might not be worth fixing depending on the value of the vehicle.


the fans workin right ... ive had brand new thermostats be stuck to .. i'd look at that next .. maybe just pull it out to see if thats the problem .. i wouldnt leave it out if it is just get another one ..


Head gasket is shot. Get a chemical analyzer and check head gasket.