OK, here's the deal. I have an 85 TA 305 V8.
About a month ago it over heated once, bottle boiled over, whole 9 yards. I let it cool down, filled it, it was fine until 2 weeks later. It over heated again same thing boiled over. Ever since the second time the temp goes up at least one everytime I drive it, even within 10 minute drives. And if I turn on the heat it drops.
I replaced the thermostat, still doing it. But I noticed that the car has only boiled over those 2 times. I just recently realized, last time the temp went up, during one of those 10 minute trips to the store, I popped my hood and it wasn't even warm.

Any ideas on what to do next?? I know its not the head or the rad. Please help. :hail: :hail: :hail:

 

check your rad cap...the car requires a 16 or 17 lb cap to pressurize the system..higher pressure means higher boiling point.