i have a 94 camaro with a 3.4L ive replaced everything in the coolant system and it still overheats..some one told me there are air bleed vavles on the block that i have to open in order to pull coolant back into the block.Is this true if so where are the vavles?Also when it is running an i hav the radiator cap off there is air bubbles coming out of the radiator and so kind of steam is coming out what is that someone told me a have a blow headgasket???

 

Read the thread titled "BAD HEAD" and that may help you. It's regarding the same thing you are asking.

 

What is the engine temperature when you see the air bubbles? If it happens also when it's cold, then yes you possibly have a blown head gasket. If it just happens when it's hot, then it's normal. Water BOILS (turns to steam which is the causes bubbling) at 212 degrees Farenheit at atmospheric pressure. With the cap off the coolant in the radiator is at atmospheric pressure.