Chrysler Repair: overheating engine, coolant temp, accurate thermometer

Question
i own a 95 chysler LHS and it seems to over heat when i have the car in park (idle) more so then when i am out driving the car. a few weeks ago i had a sensor replaced and that did not seem to fix the problem. i do not see any leaks around any of the hoses nor do see one at the radiator cap. any suggestions you could give me would be greatly appreciated.
marty  

Answer
Hi Marty,
Have you verified that the overheating (that you are detecting by the instrument panel gauge?) is actually a true excess temperature of the coolant? If you don't loose any coolant in the form of steam via the overflow bottle or the radiator cap, then I would question whether you really have an overheat problem. Try checking the temp of the coolant while it is warming up to see what it reads when your gauge is mid-scale for example. It could be an inaccurate gauge sensor.
Also, are the cooling fans coming on in series as they are designed to do? The low speed fan is supposed to come on at 199F and then the high speed fan comes on at 230F. Let me know what the fans are doing as it relates to the gauge on the dash and to any reading you can make with an accurate thermometer. I can understand that the car may run cooler when in motion than when idling because the air flow thru the radiator is increased. However, the fans should take up the slack when the car is not moving if the coolant temp rises to the control points mentioned above.
Roland