Here's the situation. Was having a coolant problem of some type, so I flushed the coolant system hoping it would fix the problem that easily. Wrong.

It stayed fine for about 6 or 7 minutes and then the temperature started to rise. After giving it another minute or two, I needed to shut the car off because it did not seem like it was going to cool itself.

What I have noticed is that all the coolant is being pushed into the coolant reservoir and not being taken out of it. This has caused the reservoir cap to pop off on one occasion. I'm quite puzzled as to why the car is not drawing the coolant out of the reservoir.

It's an 1986 FC, stock. No modifications of any type.

Thanks for the help.

Oh, also, I have already replaced the thermostat.

 

Check to see that the fan clutch is still working. When warm, see that it spins freely; with minimum resistance. If it stops within three to four turns when the engine is hot then you need a new fan.

Check the weephole on the waterpump (small hole behind the pulley, on the pump) if it is leaking then your waterpump needs to be replaced.

Various other things.... radiator cap, etc.....

 

I would do an entire cooling system shake down. Ensure every single component is operating properly such as water pump, radiator, fan clutch, etc....

 

sounds like there is air in the system. this means pulling the out the little screw on top of the radiator where the upper rad hose connects and disconnecting the coolant hose on the ACV. keep pouring in the water until it spills out these openings.
if that doesn't work then you either have a blockage or your rad cap is FUBAR!