Ok folks this problem has been plaguing me since this past spring.
My cars' temperature likes to fluctuate very badly. The gauge will tend to creep up (sometimes to the red line) and while this is happening the heater will stop working, after a little bit it will drop back down to normal temps and the heater will start working again. I have bled it and bled and it when I bleed it seems to work fine for a little while, then it comes right back after driving it around. Also the upper rad hose tends to build up ALOT of pressure and antifreeze will start to spew out from the end that connects to the radiator. I have actually already replaced the LIM gaskets but it still didn't quite help. Here is a list of everything I have done:
Replaced:
Thermostat
Water pump
Upper and lower radiator hoses
LIM gaskets (and everything above it)
Flushed:
Heater core - flowing fine
Radiator - flowing fine
I was starting to think that maybe it was a head gasket but there is no coolant in the oil and I did a compression test and this is what I got:
Cylinder 1 ~ 160 psi
Cylinder 2 ~ 160 psi
Cylinder 3 ~ 190 psi
Cylinder 4 ~ 190 psi
Cylinder 5 ~ 190 psi
Cylinder 6 ~ 190 psi
The first two cylinders were a little low, but still within 15% of the highest.
I'm almost thinking that maybe the torque isn't quite right on the left side of the engine (or front, depending on how you want to look at it) and causing air to get into the cooling system. I am completely stumped on this one. Also in case it might matter, I have switched over to the "universal" antifreeze after flushing all of the dex-cool out.