heyy, I have a 99 grand am GT and for some reason when you leave it running long enough it will shoot all of my anti-freeze out of the over flow. I've done a full flush, changed the thermostat, and taken the rad out to clean it. Even though i've done all this there still seems to be back pressure.
Also my heater doesnt work while all this is going on. When i clamped the #2 hose off in the picture below, all of the problems seem to go away and coolant starts to flow through the heating tubes again.
any suggestions would be greatly appreciated, i'd rather not have to drive around with vice grips on that hose hahah