I am not overheating. I replaced the thermostat and it runs cool, but as the engine heats up and forces fluid into the resevuar. When it cools down it does not suck the fluid back up. instead the top hose collapses from vacuum. when it is completely cool i have to remove the cap fill it back up, and bleed it to keep the buzzer from going off.

Any ideas? Could it be the sensor/valve at the top of the radiator? Thats the only thing I can think of. Whats it called?

Replace the radiator cap. Is there any smoke at start up or anything?

Lots of smoke for the first minute or so, if I give it any gas.

Coolant seals could be going forcing exhuast gas through the cooling system. The extra pressure than forces the coolant out into the overflow. But im not sure if the upper hose would act like it does if this was the case. Worst case here is that you'll need an engine rebuild soon.

I was thinking of putting some of that prestone stop leak crap in there. I have heard of people who have blown head gaskets using this and it works.

Any thoughts?