With the heat on while flushing the old coolant out with distilled water today, I noticed the temp on the thermometer I have stuck in the vent reading between 140 and 150 degrees F. That seems very high to me, but the temp gauge on the IP showed the engine temp was cool as a cucumber; steady between the C and half-way mark. I know it was about 90 degrees outside today, but the heat from the vent seemed blistering hot. Should it be this hot from the vent? If not, what might the problem be? I welcome your thoughts.

PS: Long time reader, first time post.

 

normal .. the windows raise the temp a lot thats how animals get killed

 

That might initially sound plausable, except the vent temp is still 150 F driving at night with all four windows open. I'm thinking a heater core problem, but I really have now idea at this point.

 

If the heater control **** is turned to full blue and it's still coming out hot that would suggest the heater control cable is either not connected or broke, especially if there is no tension when you turn the **** indicating it is. You can manually close the heater valve in the engine bay by the firewall by pulling it away from the firewall and see if that gets rid of the heat.