i have heard a main problem to watch on these is the lower intake gasket. it needs to be the aluminum gasket. think it was said that the older GM gaskets were nylon and would warp.

 

UPDATE!!!!
Picked up the car today at UA, added 3 bottles of water and it ran cool, but as I was driving the 1 hour drive I noticed a film on the winshield, I now think that the heater core has a small leak, it takes about 3 weeks of driving for it to over heat again. I am ordering the heater core tomorrow. I hope this solves this problem.

 

is it cold where you are at? if not you can bypass the heater core for a little bit and see if that fixes it before you dive into it. just unclamp the hoses at the fire wall and use a small piece of copper pipe to link them. if you still have your leak then you at least saved the money for the core.

 

I am in Alabama, believe it or not, I bypassed the heater core yesterday. Now I will see if that is the problem, thanks for the advise.

 

Good luck with the heater core project. I did mine last year. Make sure the tubes of the heater core are in the right position before you try to put it in. I didn't know that they rotate 180* around. Also there are plastic rivets holding the cover to the heat box on that have to be drilled out and it's kinda a pain but it's manageable. I'm gonna try to find the how to I used to do it, I don't remember where It was.

Found It.http://www.justanswer.com/uploads/as...141_ANSWER.pdf

 

this monte carlo issue is getting out of hand........let me know how the heater core works out hope you and your daughter fair a lot better than me...

 

Most part stores will rent out pressure testers for the cooling system that way you can check for leaks while engines cool

 

I changed out the heater core out yesterday, it was'nt too bad. I used a drimel grinder to remove the plastic rivets, also had to remove the seats because of the fresh air tubes that go under the seats.(which this gave me more room also) Also what I did was to drill holes where the rivets was at and used seft taping screws to attach to two covers. It was late when I got done so I have not connected the supply tubes to see how it works. The heater core was a little damp but I have a bad feeling that this did not fix it. I had a mechanic to do a pressure test on the car for a day it did not loose pressure. Problems like this make me glad I have a Corolla setting in the driveway. Venom what finally was the problem with your car?

 

my funds are a little tight right now so the resurrection problem has come to a temporary halt. she's just under a tarp in my garage i might be on track in about 2-3 weeks but thank god i have access to my moms honda and my girls kia....the mc is just sucking me dry sadly i have put more money into fixing my car then either one of them paid for theirs...

 

Wow surprised its not water pump cause by the way your saying it starts to overheat at idle then needle goes down as drive faster all signs of water pump but you say you changed so has to be heads just by the mileage on vehicle definitely stop driving you will cause more costly damage.