Pontiac Repair: Heating and Cooling, blown head gasket, pontiac sunfire

Question
I have a 1996 Pontiac Sunfire with a 2.2 engine. The other day my engine started to run hot. I changed the thermostat but it still seem to run warmer then normal. It had a new water pump put in a few month ago. Hoses all look and fell good. When I filled it back up after changing the thermostat I opened the bleeder screw to get out all the air. I remembered before that I had a hard time getting the engine to run at normal temp. after changing the hoses. Could I still have air in it because I am thinking of having the rad flushed out to see if this will improve higher then normal temp. I put in a 180 thermostat. Is there another way to make sure I still don't have a air lock or is getting the rad flushed a good idea. Also I find that when driving I find that the heat in the car go's from warm to hot then back to warm. I also took out the thermostat one day and drove to work and home and it stayed cold at the gauge. Any thought on this while I dig out of last night snow fall. THANK YOU     NORMAN

Answer
Hi Norman:

these engines are hard to bleed the air out of you are correct there is no easy way to do it. I also would put the correct theromostat back in this 195 is usually the correct temp not 180. that aside just crack the bleeder open once it's up to to opertaing temp turn the engine off before you crack it open leave the surge tank cap off don't overfill the tank but keep an eye on it so it doesn't boil over crack the bleeder open and add more to the tank it should push the air out. then start it up again and repeat a few times untill you gte no more air out. the cooling system can draw air in from the bleeder with the engine running. if you still can't get the air to bleed out I would suspect maybe a blown head gasket on this. It was pretty common for these to let go. usually they just leak coolany out the left side of the engine by #4 cylinder which is facing the front of the car on the back of the engine. good luck :)

Oh Use only 50/50 mix of dexcool and water if you get the mixture to far off of 50/50 the boil point is affected. I have also seen surge tank caps go bad on these as well the o-ring on the cap go bad and tear so it will not allow the system to build pressure thus lowering the boiling point.