ok great I hope this is the problem because if its the thermostat then I am looking at about $1800.00

 

If thermostat does not open - then you overheat, if opened all the time - you are lower temperatures.

Btw, when temperature high - could you check both pipes - going TO and FROM radiator? Should be both hot. And did you test my suggestions?

I found Behr thermostat for $100.

 

I plan on working on it this weekend. I am not great with cars so no sure how much I will get done. Thanks so much for all your help.