Help!!!!!!!! Overheating 99 Cavalier!!!

Hey guys,

I seriously need some help I've been working on my car (1999 cavalier 2.2) for a while now and can't figure it out. I originally had a small leak (couldn't figure out where) and used some of that dreaded rad leak stop gunk which did the trick.

I recently had a cracked lower hose and changed it and the car ran fine for about three days. Now it overheats when it is driving and the water spews out the overflow tank.

What I have done:

Changed thermostat - even put it into hot water to verify it was working.

Removed top and bottom hoses and flushed with a garden hose through rad and hoses, the water runs fine.

Changed water pump...old one appeared fine but changed it anyway.

Flushed entire system with flush kit!!!

The only conclusion I can come up with is that there is a blockage in the engine somewhere from the rad gunk I used. It said it was safe to stay in the engine is there anyway to flush this out without taking it to the shop??

Is there any other suggestions that could cause the overheating?? I'm all ears guys!!!! Any help would be appreciated!!

Thanks in advance,

now that that is all said and done, did you bleed the air out of the system? and how?
you said you added sealer kit and then did a flush. your system should be clean.
did you mix antifreeze for your refill?

Thanks for the reply...

I refilled it with water only because it was costing me too much in antifreeze just until I solve the problem. It's sitting in the garage so it's safe LOL...

I left the cap off and ran it for a while and it was fine. I put the cap back on and took it for a ride and within about two minutes it began spewing out the overflow tank.

I recently changed the water pump thermostat and flushed the entire system with a garden hose as well. I don't think its a blown head gasket as I have none of the symptons. The fan runs fine as well.

Is there a specific way to bleed the air from the system???

start it and let it run. at this point the rediator is full to the top and the cap is off. you should note the water level rising and lowering and it will spew over once or twice and then drop dramatically. at that time you should be there filling the system as the pump sucks in the coolant and burps the air.
This will stabelize and just wait. it will do it again, be there filling as it drops. you should be able to see the movement of water in the rad. and it should be hot, oh yea, the heater control needs to be on hot. not the fan, just the control selector.
once the coolant is flowing put the cap back on and fill the overflow to the hot line. go for a ride. arround the block and check the overflow jug. dont take off the cap. see what you have there. at this stage you should have started out with no air in the system. Also have seen bad thermostats after one days use. just a thought. you put the thermostat in the right way?

Thanks, but the system on my Cavalier does not have a radiator cap - just an expansion tank with a pressure cap. There are automatic bleed hoses from the top of the radiator and from the top hose assembly to the top of the expansion tank. When you fill the coolant up with the expansion tank cap off the air is automatically expelled. Also, the thermostat can only go in one way due to wires in the housing....

Did you try using the bleed ports? on the 2.2 there should be one on the thermostat housing and another on the metal line going to the heater core hose. To bleed you fill and cap the system and warm the engine, then slowly crack open the bleeders until just water is comming out. After this make sure the tank is full and take it for a short drive. Let it cool and then try it again if there is no air in the system then you're done, if not then keep repeating until no air. Hope this helps!

Thanks for the reply...

I have the overheating undercontrol abit....LOL...Now I can drive and it doesn't overheat just spews the coolant out the overflow when it's half full. I had a coolant flush done and it solved about 50% of my problem. If I keep minimal coolant in the car it seems to run okay runs a little hot but still okay...

I'm still at a loss...could be a clogged engine or something I'm not sure!!

After you let it run a bit- feel up and down the radiator- see if it is hot everywhere- I had a Grand Am once that did as yours does-- and the radiator had only the top two tubes functional- all others were clogged-- radiator was ice cold on all lower tubes- but too hot to touch at the top- replaced the radiator and all was fine....

That's a great point...I'll try that!!