Chrysler Repair: heating problem, chry, coolant

Question
hello Wil:
I have a 1989 chry new yorker,(laudau) 3.0L auto. In the city, driving it at around 30to40mph the temp. will raise to about center, climbing it will also heat up some but will not steam up, as soon as I'm on level ground and doing the speed limit I'm ok. I've changed the thermostat from a 195 to a 165 and it didn't help.Now during the cold months its ok but come summer it runs to hot I'm asking for your advice. thanks.
joe:

Answer
Operating temperature is straight in the center of the gauge.Putting a cooler t-stat can cause other problems.Driveability problems.Some sensors operate when the coolant hits 195.But back to your problem,if your temp rises when you put a load on the vehicle I would suspect a restriction.Most likely in the radiator and all the back flushing in the world isn't going to fix it.You should have the radiator rodded or replaced.